INFLUENCE OF PLANT

RESISTANCE IN CERTAIN

GENOTYPES OF BLACKGRAM AND

GREENGRAM ON INSECTICIDE

TOLERANCE ON Maruca vitrata

(Geyer)

L.PEDDA VENKATA REDDY B.Sc. (Ag.)

MASTER OF SCIENCE IN AGRICULTURE

(ENTOMOLOGY)

2015

INFLUENCE OF PLANT RESISTANCE IN

CERTAIN GENOTYPES OF BLACKGRAM

AND GREENGRAM ON INSECTICIDE

TOLERANCE ON Maruca vitrata (Geyer)

BY L.PEDDA VENKATA REDDY

B.Sc. (Ag.)

THESIS SUBMITTED TO THE

ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY

IN PARTIAL FULFILMENT OF THE REQUIREMENTS

FOR THE AWARD OF THE DEGREE OF

MASTER OF SCIENCE IN AGRICULTURE (ENTOMOLOGY)

CHAIRPERSON: Dr. K.V.HARI PRASAD

DEPARTMENT OF ENTOMOLOGY

SRI VENKATESWARA AGRICULTURAL COLLEGE, TIRUPATI

ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY

RAJENDRANAGAR, HYDERABAD–500 030

2015

ii

DECLARATION

I Mr. L. PEDDA VENKATA REDDY, hereby declare that the thesis

entitled “Influence of plant resistance in certain genotypes of blackgram

and greengram on insecticide tolerance on Maruca vitrata (Geyer).”

submitted to the Acharya N.G. Ranga Agricultural University, for the

degree of Master of Science in Agriculture is the result of original research

work done by me. I also declare that no material contained in this thesis has

been published earlier in any manner.

Date : L.PEDDA VENKATA REDDY

I.D. No.: TAM/2013-16

iii

CERTIFICATE

Mr. L.PEDDA VENKATA REDDY has satisfactorily prosecuted the

course of research and that the thesis entitled “Influence of plant resistance in

certain genotypes of blackgram and greengram on insecticide

tolerance on Maruca vitrata (Geyer)” submitted is the result of original

research work and is of sufficiently high standard to warrant its presentation

to the examination. I also certify that neither the thesis nor its part thereof has

not been previously submitted by him for a degree of any university.

Place :

Date : Dr. K.V.HARI PRASAD

(Chairperson)

iv

CERTIFICATE

This is to certify that the thesis entitled “Influence of plant

resistance in certain genotypes of blackgram and greengram on

insecticide tolerance on Maruca vitrata (Geyer)” submitted in partial

fulfilment of the requirements for the degree of MASTER OF SCIENCE IN

AGRICULTURE to the Acharya N.G. Ranga Agricultural University,

Hyderabad, is a record of the bonafide original research work carried out by

Mr. L. PEDDA VENKATA REDDY under our guidance and supervision.

No part of the thesis has been submitted by the student for any other

degree or diploma. The published part and all assistance received during the

course of the investigations have been duly acknowledged by the author of the

thesis.

Thesis approved by the Student’s Advisory Committee Chairperson : Dr. K.V.HARI PRASAD

Assistant Professor,

Department of Entomology,

S.V.Agricultural college,

Tirupati – 517 502, A.P.

______________

Member : Dr. T. MURALI KRISHNA

Principal Scientist,

Department of Entomology,

Regional Agricultural Research Station,

Tirupati – 517 502, A.P.

______________

Member : Dr. S. KHAYUM AHHAMMED

Assistant Professor,

Department of Plant Pathology,

S.V.Agricultural college,

Tirupati – 517 502, A.P.

______________

Member : Dr. P. LATHA

Scientist,

Department of Crop Physiology,

Regional Agricultural Research Station,

Tirupati – 517 502, A.P.

______________

Date of final viva-voce:

v

ACKNOWLEDGEMENTS

I earnestly revere the Lord for his boundless blessings, which

accompanied me in all endeavours.

I am dearth of words to express my love to my beloved parents

Smt. L. Rama Sivamma and Sri L. Lakshmi Reddy for their dedicated efforts to

educate me to this level and whose unparallel affection and persistent encouragement

will help me in keeping my career go along way throughout my life.

I am inexpressibly ecstatic to extend my deep sense of my gratitude to

luminous educationalist and esteemed chairperson of my advisory committee

Dr. K. V. Hari Prasad, Assistant Professor, Department of Entomology

S.V.Agricultural College, Tirupati, for his dexterous guidance, illuminating

suggestions and unremitting assistance throughout the period of study, research

and in completion of this thesis. I owe him a huge debt of gratitude forever for all

that I got from him.

I humbly record my heart-felt thanks to, member of my advisory

committee Dr. T. Murali Krishna, Principal Scientist Department of

Entomology, RARS, Tirupati, for his keen interest, caring attitude, valuable

guidance for sparing his precious time to improve the thesis and constant

encouragement during my research work.

With sincere regards and immense pleasure, I express my profound sense

of gratitude to the other member of my advisory committee

Dr. S. Khayum Ahhammed, Assistant Professor, Department of Plant

Pathology, S.V.Agricultural College, Tirupati, for her kind cooperation and help

rendered during my research work.

I deem it my privilege in expressing fidelity to Dr. K. Manjula, Associate

professor, Dr. A. Ramakrishna Rao, Senior Scientist, Department of

Entomology, RARS, Tirupati, Mr. E. Chandrayudu, Assistant Professor,

Dr. R. Sarada Jayalakshmi Devi Professor and Head, Department of Plant

Pathology for their help and guidance during my period of study at this college.

I am ineffable to express my esteemed thanks to, Ms. K. Devaki, Scientist,

Department of Entomology, RARS, Tirupati and, Dr. P. Sudhakar, Senior

Scientist, Dr. P. Latha, Scientist, Department of Crop Physiology, Regional

Agricultural Research Station and Dr. B. Ravindra Reddy, Assistant Professor,

Department of Statistics, S.V. Agricultural college, Tirupati for their valuable

suggestions, kind hearted cooperation and meticulous guidance showered to me.

I owe on empassing debt to my beloved Master, Dr. K.V. Hari Prasad,

who taught the concept of life. He has been a fountain inspiration throughout my

life without whose blessings in every walk of life, this work would not have been

possible.

I respectfully acknowledge my gratitude to Dr. Y. Reddi Ramu, Farm

Superintendent, Sri T. Lokhanadam, Farm Manager, Sri. Mahendra, A.E.O and

other field staff for their sustained help and cooperation during my research

work.

vi

Diction is not enough to express my feelings and affection with my brother

L.C.Venkat Reddy, sister Lakshmi whose affection, inspiration and

encouragement moulded me throughout my educational career.

With utmost satisfaction I acknowledge the enormous help of my

colleagues Peeru, Amar, Snehasish and Nischala and my juniors Naresh,

Lakshmi, Uma Mahesh, Jahnavi, Sunithama, Menaka for their friendly

assistance and special thanks to my seniors and Ph.D Scholars Shilpa, Harathi

and, Sunil, Manjunath and Devaki for beloved juniors for their help during the

course of my study.

I derive great pleasure in expressing honest appreciation to the galaxy of

friends Bhaskar, Malli, C.S, Paramesh and Yohan my seniors Ravi and Kuna

who made my stay at Tirupati a memorable and unforgettable one with their high

degree of friendliness and deep affection.

It is the right occasion to express my heartful thanks to SRFs Suma,

Sujatha and Srividhya, Aareefa,Sreenivas,Vinod Non teaching staff Murali,

Venkatesh, Prasad, Purushottam, Pandu, Varalakshmi and Pushpamma of our

department, Saradamma and Chengaiah supporting staff, Department of

Entomology, Regional Agricultural Research Station, Tirupati for their sustained

help and cooperation during my research work..

I greatly acknowledge to Venkat, Smart centre, Tirupati for neat and

timely execution of thesis work.

I am very much grateful to Acharya N.G Ranga Agricultural University,

Hyderabad for the assistance provided in the form of stipend partly supporting

my PG studies.

In finale, I thank all my well wishers and others who helped me directly or

indirectly not placed here, for their kind cooperation and support rendered to

me.

L.P. Venkat…

vii

LIST OF CONTENTS

Chapter No. Title Page No.

I INTRODUCTION

II REVIEW OF LITERATURE

III MATERIAL AND METHODS

IV RESULTS AND DISCUSSION

V SUMMARY AND CONCLUSIONS

LITERATURE CITED

viii

LIST OF TABLES

Table

No. Title

Page

No.

4.1 Percentage infestation of Maruca vitrata in different districts of

southern zone of Andhra Pradesh

4.2 Varieties preferred by the farmers in southern zone districts of

Andhra Pradesh

4.3 Insecticide usage by the farmers of Southern zone of Andhra

Pradesh against Maruca vitrata infestation

4.4 Number of webbings of M.vitrata larva per plant in different

genotypes of blackgram

4.5 Total number of M.vitrata caterpillars per plant in different

genotypes of blackgram

4.6 Percentage infestation of M.vitrata in different genotypes of

blackgram

4.7 Number of webbings of M.vitrata larva per plant in different

genotypes of greengram

4.8 Total number of M.vitrata caterpillars per plant in different

genotypes of greengram

4.9 Percentage infestation of M.vitrata in different genotypes of

greengram

4.10 Number of webbings of M.vitrata larva per plant in different

genotypes of greengram

4.11 Total number of M.vitrata caterpillars per plant in different

genotypes of greengram

4.12 Percentage infestation of M.vitrata in different genotypes of

greengram

4.13 Larval preference of Maruca vitrata on different genotypes of

blackgram in free choice experiment

4.14 Biology of M.vitrata in resistant, moderate resistant and

susceptible genotypes of blackgram in no choice technique

4.15 Larval preference of Maruca vitrata on different varieties

of greengram in free choice experiment

4.16 Biology of M.vitrata in resistant, moderate resistant and

susceptible genotypes of greengram in no choice technique

4.17 Physical characters of resistant, moderate resistant and

susceptible genotypes of blackgram

4.18 Biochemical characters of resistant, moderate resistant and

susceptible genotypes of blackgram

ix

Table

No. Title

Page

No.

4.19 Correlation study of M.vitrata growth parameters and blackgram

characters (physical and biochemical)

4.20 Regression study of M.vitrata growth parameters and blackgram

characters (physical and biochemical)

4.21 Physical characters of resistant, moderate resistant and

susceptible genotypes of greengram

4.22 Biochemical characters of resistant, moderate resistant and

susceptible genotypes of greengram

4.23 Correlation study of M.vitrata growth parameters and

greengram characters (physical and biochemical)

4.24 Regression study of M.vitrata growth parameters and greengram

characters (physical and biochemical)

4.25 Tolerance of larvae of Maruca to chlorpyriphos on resistant and

susceptible genotypes of blackgram

4.26 Tolerance of larvae of Maruca to chlorpyriphos on resistant and

susceptible genotypes of greengram

x

LIST OF PLATES

Plate.

No. Title

Page

No.

3.1 Mass multiplication of spotted pod borer

4.1a Collecting information from the farmer

4.1b Conducting Roving survey in farmers field

4.2 Screening of blackgram and greengram genotypes for Maruca

infestation

4.3 Biology studies on different genotypes by free-choice and

no-choice techniques

4.4 Insecticidal resistance by topical bioassay studies

xi

LIST OF SYMBOLS AND ABBREVIATIONS

% : Per cent

@ : At the rate of

a.i : Active ingredient

°C : Degree centigrade

cm : Centimetre

mm : Millimetre

m : Metre

m2 : Squre meter

et al., : And others

Fig. : Figure

i.e. : That is

viz., : Namely

etc : and so on; and other people/ things

µg : Micro gram

mg : Milligram

ml : Milli litre

ml l-1 : Millilitre per litre

g l-1 : Gram per litre

LD50 : Median Lethal Dose

mg g-1 : Milligram per gram

kg ha-1 : Kilogram per hectare

m ha : Million hectares

LC50 : Lethal concentration

DMRT : Duncan's Multiple Range Test

r : Correlation coefficient

R2 : Regression coefficient

M : Molarity

N : Normality

pH : Potential of hydrogen ion concentration

rpm

: revolutions per minute

Name of the Author : L. PEDDA VENKATA REDDY

Title of thesis : “INFLUENCE OF PLANT RESISTANCE IN

CERTAIN GENOTYPES OF BLACKGRAM

AND GREENGRAM ON INSECTICIDE

TOLERANCE ON Maruca vitrata (Geyer)”

Degree to which it is

submitted

: MASTER OF SCIENCE IN AGRICULTURE

Faculty : AGRICULTURE

Major field : ENTOMOLOGY

Chairperson : Dr. K. V. HARI PRASAD

University : ACHARYA N.G. RANGA AGRICULTURAL

UNIVERSITY

Year of submission : 2015

ABSTRACT

The present study on “Influence of plant resistance in certain genotypes of

blackgram and greengram on insecticide tolerance on Maruca vitrata (Geyer)” was

carried out in Department of Entomology, S. V. Agricultural College, Tirupati. Before

commencement of the work, a survey was conducted during late kharif, 2014 in three

districts of the Southern zone (Nellore, Kadapa and Chittoor districts) of Andhra Pradesh

for information on per cent Maruca infestation, genotype preference (blackgram and

greengram) by the farmers and insecticidal usage against spotted pod borer. Maruca

infestation was seen more in Kadapa district both in blackgram and greengram. In

blackgram, the genotype LBG-752 (62.2 %) and in greengram LGG-460 genotype (59.3 %)

occupied more area in cultivation. Among the insecticides, the Chloropyriphos was used

more i.e., 51.9 % in blackgram and 54.1 % in greengram in the Southern zone against the

spotted pod borer infestation.

A screening experiment was conducted with nine genotypes of blackgram

(LBG-685, PU-31, LBG-20, LBG-790, LBG-752, LBG-792, LBG-123, LBG-791,

LBG-645) and ten genotypes of greengram (WGG-42, LGG-407, PM-115, MGG-360,

PM-110, LGG-410, PM-112, TM-962, LGG-450, LGG-460) in wetland farm, S.V.

Agricultural College, Tirupati. From the field data, blackgram genotypes LBG-645,

LBG-791 and LBG-790 and greengram genotypes WGG-42, TM-960 and MGG-360

were selected and classified as a resistant, moderate resistant and susceptible genotypes

based on number of Maruca webbings per plant and number of Maruca caterpillars per

plant. Further investigations on these genotypes under laboratory conditions have given

similar trends observed in the field investigations. In a free-choice arena test, in

blackgram the larval orientation was seen more in LBG-790(2.57 ± 0.98) followed by

LBG-791 (1.86 ± 0.69) and least in LBG-645(1.57 ± 0.53) and in greengram, more in

MGG-360 (2.57 ± 0.79) followed by TM-962(1.86 ± 0.69) and lowest in WGG-42(1.57

± 0.53). The duration of the 2nd instar, 3rd instar, 4th instar, 5th instar, total larval

duration, pupal duration and adult longevity was seen more on resistant genotypes than

on moderate resistant and susceptible genotypes of blackgram and greengram and the

weight of 3rd instar larva,4th instar larva and pupal weights were less on resistant

genotypes compared to moderately and susceptible genotypes.

When biophysical and biochemical constituents of the blackgram and greengram

genotypes were correlated with that of the insect growth parameters, it was found that

the larval orientation had a positive correlation with proteins and reducing sugars.

Chlorophyll content showed a positive correlation with weights of larvae and pupae and

negative correlation with the duration of pupae and adult. Phenols showed a positive

correlation with the duration of the larvae, pupae and adults and negative correlation

with the weight of the larvae and pupae. Proteins and reducing sugars showed a

negative correlation with the duration of the larvae, pupae and adults and positive

correlation with the weight of the larvae and pupae.

In topical bioassay experiment, LC50 and LD50 values of Chlorpyriphos to

Maruca larvae reared on resistant genotypes of blackgram and greengram was less as

compared to LC50 and LD50 values of Chlorpyriphos to Maruca larvae reared on

susceptible genotypes of blackgram and greengram.

Chapter I

INTRODUCTION

Pulse crops play an important role in maintaining soil health and supplying

protein to large masses of the people in this country. India grows a variety of pulse

crops under a wide range of agro-climatic conditions and has a pride of being the

world’s largest producer of pulses. The most commonly grown pulses in India

include chickpea, pigeonpea, blackgram, greengram, fieldbean, horsegram, etc.

Pulses form an important component of Indian agriculture, in view of their unique

capacity to fill the dietary requirements of majority of vegetarian population of rural

India, besides replenishing soil fertility through their sustainable characters. India

cultivated pulses in 232.56 lakh hectares with an average production of 18.34 million

tonnes in 2012-13 (Annual Report of Department of Agriculture and Cooperation,

2013-2014).

Blackgram (Vigna mungo (L) Hepper) and Greengram (Vigna radiata (L)

R.Wilczek) are the two important short-duration pulse crops grown in many parts of

India. These crops are grown in different cropping systems as a mixed crop, catch

crop, sequential crop, besides as sole crop under residual moisture conditions after

the harvest of paddy and also before and after the harvest of other summer crops

under semi-irrigated and dry land conditions. In India, blackgram and greengram are

very popularly grown in Andhra Pradesh, Bihar, Madhya Pradesh, Maharashtra,

Uttar Pradesh, West Bengal, Punjab, Haryana, Tamil Nadu and Karnataka with an

area of about 4.29 million hectares with a total production of 1.90 million tonnes

with an average productivity of 485-500 kg ha-1 (Directorate of Economics and

Statistics, Government of Andhra Pradesh, 2011-12). Andhra Pradesh ranks first in

productivity followed by Orissa. In Andhra Pradesh, the maximum area under these

crops during kharif is in coastal region with Guntur district ranking first in

production in Andhra Pradesh.

Both blackgram and greengram are affected by important insect pests such as

spotted pod borer, Maruca vitrata (Geyer), plume moth, Exelastis atomosa

(Walsingham), gram pod borer, Helicoverpa armigera (Hubner), red hairy

caterpillar, Amsacta moorei (Butler) and leaf hopper, Empoasca kerri (Pruthi).

About 15-30 % of the yield loss occurs due to insect pests in pulse crops (Tripathi

et al., 2015).

The spotted pod borer, M vitrata is a serious pest of grain legume crops

including mungbean, urdbean, pigeonpea and common beans (Chandrayudu et al.,

2006). It attacks crops right from the pre-flowering to pod maturing stage causing

considerable yield loss. Singh (1999) reported 70-80 % yield loss in pigeonpea,

whereas it was 17-53 % in cowpea (Liao and Lin, 2000) and

100 % in urd bean (Giraddi et al., 2000). In pigeonpea, losses due to M. vitrata have

been estimated to be $ US 30 million annually (ICRISAT, 1992). Vishakantaiah and

Jagadeesh Babu (1980) observed between 9 and 51% infestation in red gram.

The larvae of M. vitrata feeds on flowers, buds, and pods by webbing with leaves

(Sharma et al., 1999). This webbing behaviour protects the larvae from both biotic

and abiotic conditions and this behaviour also makes it difficult to manage the insect

by synthetic chemicals. The repeated use of older class chemicals such as

chlorpyriphos, acephate, dichlorovos etc., have resulted in development of resistance

to insecticides. Presently, attempts are being focused on use of safer insecticides,

plant products and microbial pesticides to reduce the resistance development and to

maintain safety of the environment. Host Plant Resistance offers one of the best

insect pest management strategy which is environmentally safe and with no

additional cost incurred to the farmers.

A lot of work has been done on screening of various genotypes, germplasm,

wild relatives of different pulses to different insect pests feeding on them. An ample

amount of work has also been carried out on knowing mechanism of resistance

involved and role of secondary metabolites on plant resistance to insects. Quite few

numbers of insect resistant genotypes has also been released by state, national and

international institutes. However not much work has been done on host plant

resistance to spotted pod borer in black gram and green gram and its interaction with insecticide tolerance. Keeping these research gaps in view, the present work is

planned with the following objectives.

Objectives:

1. Survey on incidence of M. vitrata on blackgram and greengram and

insecticide usage in major growing areas of southern zone of Andhra Pradesh

during late kharif, 2014.

2. Screening of various blackgram and greengram genotypes to M.vitrata

infestation.

3. To study the mechanisms of resistance in popular varieties of blackgram and

greengram for M. vitrata.

4. To study the effect of plant resistance in popular varieties of blackgram and

greengram to M. vitrata and its role in insecticide tolerance.

Chapter II

REVIEW OF LITERATURE

The spotted pod borer, Maruca vitrata (Geyer) derives its predominant

importance as a pest of tropical grain legumes from its extremely wide geographical

distribution, extreme host range and its ability to infest the young growing plant tips,

stems,flower buds, flowers, pods and seeds. M. testulalis [M. vitrata] (Lepidoptera:

Pyraustidae) was recorded for the first time during 2001 as a pest of pigeonpea in

Manipur, India (Devi and Singh, 2001). The destructiveness at critical stages of growth

viz., flowering and seed production constitutes a significant constraints to the

productivity of grain legumes (Taylor, 1967 and Raheja, 1974). This pest is known by

different vernacular names in different countries, katajang moth in indonesia (Dietz,

1914), limabean pod borer in puerto rico (Leonard and Mills, 1931), legume pod borer

or cowpea pod borer in kenya (Okeyo-owuor and Ochieng, 1981), avare pod borer and

tur web worm, Maruca testulalis or Maruca vitrata (Geyer) in India (Krishna murthy,

1936; Vishakantaiah and Jagadeesh Babu, 1980) respectively. In this chapter, work

carried out on the survey, varietal screening, morphological and biochemical characters

of blackgram and greengram, biology and insecticidal evaluation against M.vitrata have

been reviewed.

2.1 SURVEY FOR THE INCIDENCE OF Maruca vitrata.

Maruca testulalis [M. vitrata] was recorded from Vigna mungo during early pod

formation in August, 1988 in Dharwad, Karnataka, India. Larvae of the pest were

observed boring into the stems of 8-15% of the crop from the axils of the branches and

the affected branches later wilted and dried up (Goud and Vastrad, 1992).

Lalasangi (1988) observed parasitoids viz., Bracon greeni and Apanteles

taragamae on Maruca testulalis [M. vitrata] on cowpea (Vigna unguiculata) in

Karnataka, India, in May-January with peak incidence in July, August and October

Studies at two sites in western kenya during 1983-85 revealed the presence of at

least seven parasitoids and two predators attacking Maruca testulalis on cowpea and the

Antrocephalus sp. was the predominant parasitoid (Okeyo-Owuor, 1991).

Ganapathy and Durairaj (1995) observed that redgram was predominantly

infested with Helicoverpa armigera and Maruca testulalis and blackgram and

greengram were predominantly infested with Madurasia obscurella and Bemisia tabaci

during survey conducted in 1989-91 in the Pudukottai district of Tamil Nadu.

Quadrant method (QM) and plant inspection method (PM) were tested as

sampling techniques for the development of Maruca testulalis [M. vitrata] on pigeon

peas cv. T21 during kharif 1994 in Assam, India. Number of larvae, infested flowers

and infested pods/plant were counted on 20 plants/plot in PM, relative variation and

relative net precision were also calculated. PM was found to be the more cost effective

method (Kalita and Dutta, 1995).

In a field study in 1994-1995 at six sites in Sri Lanka, Maruca testulalis

(M.vitrata), Helicoverpa armigera, Exelastis sp, Lampides sp, Melangromyza obtusa,

Mylabris sp and Sphenoptera sp were identified as pests of pigeonpea. Of these, the

most damaging was M.Vitrata (Bhagwat et al., 1996).

Surveys were carried out during kharif 1996 in Madhya Pradesh, India, to

investigate the incidence of Maruca testulalis in pigeonpea and observed that about a

total of 50-60 per cent of plants was damaged by larvae ( Singh, 1997).

A field survey for natural enemies of M. testulalis [M. vitrata] was conducted in

Jorhat, Assam, India, during 1997-98. The result revealed the presence of 6

hymenopterous parasitoids (Caenopimpla sp., Bracon greeni, Meloboris sp., Temelucha

sp., Phanerotoma sp. and Cotesia sp.) and 5 species of predators (Oxyopes shweta,

Thomisus katrajghatus, Thomisus sp., Antilochus coquebertii and Salticus sp.) (Borah

and Dutta , 2001).

A survey of parasitoids of M. testulalis [M. vitrata] was conducted in various

parts of the Central Brahmaputra Valley Zone of Assam, India, during 2002/03. The

larvae and pupae of M. testulalis were collected from mung bean and urd bean [Vigna

mungo] fields during the summer and kharif seasons The survey revealed the presence

of Caenopimpla sp., Phanerotoma sp., Temelucha sp and Bracon greeni. Parasitism

ranged from 1.72 to 23.44% in 2002 and 0.83 to 20.56% in 2003. Total parasitism by

the parasitoid complex reached 69.94 and 60.83 % in 2002 and 2003, respectively

(Borah and Sarma, 2004).

In Pantnagar, Uttarakhand, India, adults and nymphs of Canthecona furcellata

[Eocanthecona furcellata] were found feeding on the larvae of M. vitrata on Cajanus

cajan from the 38th standard week to the 46th standard week in 2008. This is thought to

be the first report of Canthecona furcellata predation on M. vitrata (Nebapure and

Meena, 2011).

Rani et al. (2013) observed that among the coccinellids, Chelomenes

sexmaculata species were only observed in Pulses ecosystem and among spiders,

ground spiders viz., Urocteid species, Sparassus pseudolamarckii, Lycosids

arctosamulani, Hippasa spp, Salticius spp in blackgram and greengram ecosystems.

Other spiders, Argiope spp, Oxyopes spp, Thomisus spp, Chrysilla spp, Tetragnatha

spp, Neosconathei si, Curba spp were noticed in pulses ecosystems during survey

conducted in twelve mandals of Khammam district.

The survey, conducted for two consecutive years (2009-10 and 2010-11) in the

twelve major greengram growing mandals of Khammam district during summer, at

different growth stages of pulses from randomly selected five farmer's fields revealed

that the M. vitrata larval incidence ranged from 5-15 larvae per twenty five plants in

bud initiation, flowering and podding stages. The flower infestation ranged from

11.5-29% whereas pod damage ranged from 18-27.5%. Among the surveyed mandals,

Thirumalayapalem (27.5%), Khammam Urban (24%) and Penubally (23%) recorded

the highest pod damage, whereas Madhira (18%) & Bonakal (19.5%) recorded the

lowest pod damage (Rani et al., 2013).

A survey was conducted to determine the presence of insect pests in field bean

(Dolichos lablab [Lablab purpureus]) plantations, Yavatmal, Maharashtra, India, and

observed that the field bean raised in September was almost free from pests for

a month but was later infested by Colemania sphenariodes, Cosmopteryx phaeogastra,

Hedylepta indicata, Euproctis subnotata, Empoasca spp,

Aphis craccivora, Megaleurothrips usitatus, Sphenarches anisodactylus, Adisura

atkinsoni, Helicoverpa armigera, Maruca testulalis, Riptortus linearis and Nezera

viridula (Ghuguskar, 2001).

2.2 SCREENING OF VARIOUS PULSE CROPS FOR RESISTANCE

TOWARDS M.vitrata.

Sahoo et al. (1989) have screened 60 Vigna radiate and 50 V. mungo genotypes

in the field for resistance to M. vitrata during 1985-87 and observed that the V.

mungo genotype, B3-8-8 and V. radiata genotypes, PDM54-146, ML131 and ML372

were shown resistance nature.

Sontakke and Muduli (1990) evaluated 21 varieties of greengram [Vigna

radiata] and 10 of blackgram [V. mungo ] in the field in India in 1988-89 for resistance

to a complex of pod-boring lepidoptera that includes Catachrysops cnejus [Euchrysops

cnejus], Maruca testulalis, Lampides boeticus and Heliothis armigera [Helicoverpa

armigera] and observed that the infestation ranged from 6.5 to 38.0% in greengram,

and from 8.9 to 22.6% in blackgram for the different varieties.

Oghiakhe et al. (1995) have screened eighteen cowpea cultivars for resistance to

the pyralid, Maruca testulalis[M. vitrata] under field conditions at two locations

(Mokwa and Ibadan) in Nigeria. For percentage pod damage at both locations, TVu

946, MRx2-84F and MRx109-84F were the best three cultivars while IT82D-716 was

the worst. Yield reduction caused by M. vitrata at Ibadan ranged from 3.47% in

MRx2-84F to 49.75% in IT82D-716; at Mokwa values ranged from 10.65% for

MRx54-84M to 52.23% for MRx15-84F.

Huang HuiYing (1999) has evaluated forty varieties of asparagus bean, Vigna

unguiculata ssp. sesquipedalis for their effects on a population of Maruca testulalis

[M. vitrata] at the vegetable farm of South China University over 3 years and observed

the variety, Xinqing had the lowest larval populations in all 3 years.

Vidya and Oommen (2001) screened 50 genotypes of yard-long bean [Vigna

unguiculata (L.) to evaluate legume pod-borer [Maruca vitrata (Fabr.)] resistance and

observed the genotype, Vs 5 was the most resistant one among the fifty genotypes.

Mohapatra and Srivastava (2002) evaluated 20 early-maturing pigeon pea

genotypes against legume pod borer, M. vitrata and observed that the incidence

of M.vitrata population was significantly highest in ICPL 98016 (1.38 webs and 2.09

larvae per plant at 15 days after flowering (DAF), and 1.48 webs and 1.92 larvae per

plant at 30 DAF) and lowest in ICPL 98013 (1.11 webs and 1.54 larvae per plant at 15

DAF, and 1.18 webs and 1.47 larvae per plant at 30 DAF). The pod and locule damage

percentages were significantly lowest in ICPL 98009 (17.16 and 12.52%, respectively).

ICPL 98009, ICPL 98013 and ICPL 98014 were the least susceptible genotypes to pod

borer.

Sahoo et al. (2002) have evaluated 21 early maturing pigeon pea genotypes

against the incidence of Maruca testulalis and pod borer complex during 1994-95 and

1995-96 kharif seasons and observed that the genotypes AS 46, T 21, ICPL 83024, AS

36, H 82-1 and H 89-2 were found resistant to the insect pests complex.

Saxena et al. (2002) have screened 271 pigeonpea genotypes for resistance to

M.vitrata and observed that the nondeterminate genotypes (41-50%) showed resistance

against spotted pod borer infestation than the determinate genotypes (66-75%).

Srivastava and Mohapatra (2002) evaluated fifteen medium duration pigeon pea

genotypes, during the kharif season of 1998 to study the extent of pod damage due to

lepidopterous pod borers (LPBs) including spotted pod borer and observed that the

genotype, ICP 8863 suffered the highest pod damage caused by LPBs, while the lowest

was in KM 124 and KM 125.

Durairaj and Shanower (2003) screened four determinate (ICPL 151, ICPL 4,

ICPL 86012 and ICPL 87) and four indeterminate (ICPH 8, ICPL 88034, ICPL 2

and UPAS 120) pigeon pea genotypes for resistance to pod borers (Helicoverpa

armigera and Maruca vitrata) and observed that the genotype ICPL 4 recorded the

lowest average percentage of damage by pod borers (41.6%).

Mohapatra and Srivastava (2003) evaluated four pigeonpea genotypes and

observed ICPL 98001 and ICPL 87 which were of determinate types were more

susceptible to M.vitrata compared to ICPL 98012 and UPAS 120 which were of

indeterminate types.

Mandal (2005) has screened pigeonpea genotypes to determine the resistance to

pod borers, i.e., Maruca testulalis and Helicoverpa armigera and observed that four

short duration genotypes, i.e., ICPL 85055, ICPL 85015, ICPL 84067 and ICPL 84032,

and 2 medium duration genotypes, i.e. ICPL 306 and ICPL 850046 were resistant to

pod borers registering 5.1 to 10% pod damage.

Mandal (2005 a) evaluated 18 genotypes of greengram for identifying resistance

to pod borers, i.e., Maruca testulalis [Maruca vitrata] and Lampides boeticus and

observed that the genotypes ML 5, ML 408 and RMG 266 were resistant (less than 5%

pod damage), the genotypes ML 131, ML 505, RMG 275, Pusa 8971 and Pusa 8972

were moderately resistant (5.1-10% pod damage); PDM 219, RMG 175, RMG 202,

Pusa 8974, Pusa Baisakhi and K851 were moderately susceptible (10.1-15% pod

damage); PDM 216, ML 537, PDM 86-199 and WBM 202 were susceptible (>15% pod

damage).

Mandal (2005 b) has screened 16 genotypes of ricebean for resistance to pod

borers i.e., Maruca testulalis [Maruca vitrata] and Lampides boeticus and observed that

the genotypes SRBS 113 and RBL 1 were considered as resistant, recording 5.1 to 10%

pod damage.

Ritu Srivastava and Sehgel (2005) screened 15 pigeonpea genotypes against pod

borer complex and observed that among the genotypes, MPG 537, ICPL 151 and ICPL

88034 were the least susceptible to Maruca testulalis [Maruca vitrata].

Krishna et al. (2006) have evaluated 25 blackgram genotypes for resistance

to M. vitrata and based on pod damage, the genotypes were classified as resistant

(0-12% damage; LBG 745, LBG 747, LBG 744, LBG 726 and LBG 762), moderately

resistant (>15% damage; LBG 764, LBG 761, LBG 738, LBG 730, LBG 755, LBG

749, LBG 746, LBG 765 and LBG 727), moderately susceptible (more than 25%

damage) or susceptible (more than 35% damage).

Krishna et al. (2006) have screened 25 blackgram genotypes for resistance

to M. vitrata and based on the mean values of standard deviation for larval incidence

per 10 plants, the genotypes were classified as resistant (LBG 726, LBG 762, LBG 745,

LBG 747 and LBG 744), highly susceptible or susceptible. The genotypes were also

categorized as resistant (LBG 726, LBG 762, LBG 745, LBG 747 and LBG 744),

highly susceptible or susceptible based on mean values of standard deviation for per

cent pod damage. The results indicated that LBG 762, LBG 726, LBG 747, LBG 744

and LBG 745 were resistant to M. vitrata.

Obadofin (2007) screened 12 genotypes of cowpea for resistance to major insect

pests over two planting seasons (2002 and 2003) and observed that all the genotypes

were shown resistant to Maruca testulalis.

Adekola and Oluleye (2008) evaluated some cowpea mutants for identifying

resistance source to M. vitrata. Fifteen selected cowpea mutants with the parent,

‘IT84S2246 D’ as a susceptible check and a resistant check ‘Tvu 946’ in an intensive

free choice test. The results showed that there was a significant variation in the level of

resistance among plant types with Mutant 4 recording a yield loss of 46.1% as

compared to 75.1% in parents.

Seven parents (CO 6, CO 5, LRG 41, VRG 17, APK 1, ICPL 87119 and ICPL

332) and twelve F1 hybrids of pigeonpea were utilized for the screening. Considering

the resistance to spotted pod borer (Maruca testulalis) and blister beetle (Mylabris

pustulata) under unprotected field conditions, LRG 41 recorded the highest grain yield

with lowest yield loss followed by ICPL 332. The hybrid LRG 41 x ICPL 87119

registered the highest yield coupled with lowest yield loss followed by CO 6 x ICPL

87119 (Anantharaju and Muthiah, 2008).

Rani et al. (2008) have screened 12 greengram genotypes at the Agricultural

Research Station, Madhira continuously in kharif and rabi for 3 years from 2004 to

2006 and observed that the genotypes MGG 366 358, MGG 359, MGG 360, MGG 364

and MGG 367 were tolerant to the pod borer damage in both kharif and rabi seasons

compared to the moderately susceptible check, MGG 295.

Sunitha et al. (2008) have evaluated 6 promising short duration pigeon pea

genotypes and observed lower pod damage by M. vitrata in ICPL 98003 and ICPL

98008 compared to the susceptible genotype, ICPL 88034.

Jaydeep Halder and Srinivasan (2012) screened 5 host plants for host preference

of M. vitrata and observed the highest number of larval population was noticed on

cowpea (20.4/plant), followed by urd bean (8.0/plant) and mung bean (7.1/plant), while

field bean (4.3/plant) and pigeon pea (2.6/plant) were on par with each other. The

highest incidence on flower and flower buds was recorded in cowpea (46.1%), followed

by field bean (15.4%) and urd bean (11.0%). The pod damage followed the same trend.

Ogah and Ogah (2012) evaluated African yam bean (Sphenostylis stenocarpa)

varieties for resistance to M. vitrata and of all the varieties assessed, TSs9 was the most

resistance and differed significantly (P<=0.05) from the rest of the varieties; while

TSs84 was the most susceptible with poorest grain yields.

Arvind et al. (2013) have screened 1 promising variety Pusa Komal and 14

genotypes of cowpea against legume pod borer (Maruca testulalis). The maximum

population of pests was recorded as 0.83 pod borer larvae per flower bud at 91 DAS

during second week of November and 2.18 per pod at 84 DAS during first week of

November. The pod damage among the test cultivars varied from 22.8% to 32.56% by

pod borers and genotype KCP-6 was least susceptible, whereas KCP-1 was most

susceptible to this pest. None of the cultivars was found resistant to this pest.

Randhawa (2013) has screened 15 genotypes and two check varieties of

pigeonpea to spotted pod borer, M. vitrata and genotype, AL 1743 was found promising

with mean of 14.33 larvae/100 flower buds as compared with 28.00 larvae on AL 1811.

2.3 PHYSICAL AND BIOCHEMICAL MECHANISMS OF RESISTANCE

AGAINST SPOTTED POD BORER

2.3.1 Physical Characters

Jackai and Oghiakhe (1989) demonstrated the role of pubescence and trichomes

in 2 wild cowpea genotypes, TVNu 72 and TVNu 73, to feeding and damage caused by

Maruca testulalis and Clavigralla tomentosicollis and observed that feeding and

development were deterred in both insects on pods of TVNu 72 and TVNu 73 with or

without trichomes compared to the susceptible variety, IT84E-124. It was concluded

that resistance to M. testulalis was based on trichomes in the first instance as a first line

of defense. Glandular and non-glandular trichomes were found to be present on both the

cultivated and wild cowpea. Trichomes in the 2 types of cowpea differ significantly

only in trichome number (susceptible cultivated cowpeas have more) and non-glandular

trichome length (those on wild cowpea are 20 times longer). Trichome length and angle

to pod surface seemed to be more important than density per se.

Oghiakhe et al. (1991) have reported the anatomical features of cowpea

associated with stem and pod wall that confers resistance to Maruca testulalis. The

anatomical microenvironment of the area close to the stem epidermis seemed to impose

severe limitations on larval movement and feeding within tissue. Collenchyma cells in

both 21-day-old TVu 946 and IT82D-716 stems formed a network of closely knit

interlocking cells with a few intercellular spaces. Significant differences were observed

in the distance between the epidermis and collenchyma cells of the slightly raised

(convex) and concave portions of TVu 946 and IT82D-716 stems. TVu 946 had a

smaller stem diameter than IT82D-716 stem. Distance between epicarp and mesocarp

tissues of 7-day-old TVu 946 and IT82D-716 pod wall did not show any significant

difference. Stem anatomy was considered to be an important factor in stem resistance

to M. testulalis, but this did not appear to be the case in pod wall resistance.

Oghiakhe et al. (1992) have studied the effect of pod angle on the resistance of

cowpea genotypes to Maruca testulalis using the susceptible cultivar, IT82-D-716 and

the resistant cultivar, TVu 946. Three different pod angles were used in the study: a

normal angle, a decreased angle and an increased angle. Negative and highly significant

(P <0.01) relationships were observed between pod angle and percentage pod damage,

as well as the seed damage index in the 2 cowpea cultivars. Pods with wide angles

(>=89 degrees) were damaged on only one and rarely on both pods.

Oghiakhe et al. (1992 a) have recorded the effect of pod wall toughness in the

resistance of cowpeas to Maruca testulalis and observed that there was a positive and

significant correlation (r = 0.82) between pod age and the amount of pressure required

to penetrate the pod wall. No significant differences (P >0.05) were observed in non-

intact pod wall toughness between the resistant (TVu 946) and susceptible (IT82D-716)

cowpea cultivars at all the growth stages tested. However, significant differences

(P <0.05) were observed between these 2 cultivars for only 6-day-old intact pods,

where IT82D-716 recorded a higher value than TVu 946.

Oghiakhe et al. (1992 b) have studied the role of trichomes in damage to cowpea

by the M. vitrata and observed that trichome cover on individual cultivars (IT82D-716

(susceptible), MRx2-84F (moderately resistant) and Tvu 946 (resistant)) varied in

trichome length and density, but not in trichome type from different plant parts.

Oghiakhe et al. (1993) have reported the anatomical basis of resistance of Vigna

vexillata (Acc. TVNu 72) to Maruca vitrata and observed that the presence of

uncharacteristic network of fibrous structures on the petal surface, presence of more

trichomes, presence of more gap between the pod wall epicarp and mesocarp confers

resistance in TVNu 72, but not on that of the susceptible genotype, IT82D-716.

Oghiakhe (1997) has demonstrated the morphological characters viz., trichomes,

hair-like outgrowths from the epidermis of aerial plant parts of cowpea genotypes, and

eventhough they were eliminated from cultivars by selection, they showed great

promise towards the development of multiple pest-resistant. Highly pubescent

wild Vigna species had shown good levels of resistance to the Maruca vitrata.

Veeranna and Hussain (1997) recorded the different physical parameters in 45

cowpea genotypes for the resistant/susceptible to Maruca vitrata infestation and

observed that the most resistant genotype (TVX-7) had a high trichome density

(24.41/9 mm2), while the most susceptible genotype (DPCL-216) had a low trichome

density (12.82/9 mm2), confirming earlier findings that trichomes are important in

reducing attack by the pest.

Jaydeep Halder and Srinivasan (2005) studied on different plant parameters,

i.e., pod wall thickness, number of pods per cluster, angle between the pods, trichomes

on leaves, pods and stem, trichome length, pod length and pod width, on the expression

of varietal reaction towards spotted pod borer in the urd bean cultivars LBG-17, LBG-

22, LBG-623, LBG-402, LBG-20, T-9, LBG-685, PBG-1, PBG-7 and LBG-611. The

highly susceptible LBG-17 had the least number of trichomes on stems (14.7), pods

(3.4) and leaves (4.5) compared to the highly tolerant LBG-611, which had 20.3, 10.1

and 8.2 trichomes per mm2, respectively. Similarly, trichome length was also least (0.95

mm) in LBG-17 compared to LBG-611 (2.4 mm). The pod wall thickness, angle

between the pods and pod width showed a negative correlation with pod damage. LBG-

17 possessed the lowest pod wall thickness (0.52 mm), least pod width (5.2 mm) and

minimum pod angle (40 degrees) compared to LBG-611 (0.58 mm, 5.96 mm and 89

degrees, respectively). Similarly, the highest pod length (6.1 cm) and maximum number

of pods per cluster (7.2) were recorded from LBG-17 compared to the other cultivars.

Chandrayudu et al. (2006) have recorded the incidence of M. vitrata in field

bean, cowpea, pigeon pea, mung bean and urd bean in relation to plant biophysical

characters, i.e., number of trichomes and pod wall thickness and found that cowpea and

field bean were the most preferred hosts of M. vitrata.

Jayadeep Halder et al. (2006) have demonstrated the different plant parameters,

i.e., pod wall thickness, number of pods/cluster, angle between the pods, trichomes of

leaves, pods and stems, trichome length, pod length and pod width, in relation to the

expression of varietal reaction towards the spotted pod borer Maruca vitrata in 10

mung bean cultivars (LGG-450, LGG-460, LGG-792, LGG-485, LHH-483, LGG-489,

LGG-407, LGG-523, MGG-348 and LGG-497). It was observed that highly susceptible

LGG-450 had the least number of trichomes on stems (8.9), pods (3.0) and leaves

(13.0) compared to the highly tolerant LGG- 497 which had 12.3, 7.2 and 22.8

trichomes/mm2 on the stems, pods and leaves, respectively. Similarly, trichome length

was also least (0.46 mm) in the susceptible LGG-450 compared to the resistant

LGG497 (0.62 mm). Pod wall thickness, angle between the pods and pod width showed

negative correlation with pod damage. The highly susceptible LGG-450 possessed the

lowest pod wall thickness (0.50 mm), least pod width (4.03 mm) and minimum pod

angle (38 degrees ) compared to the most tolerant LGG-497 (0.55 mm, 4.90 mm and 85

degrees , respectively).

Kamakshi and Srinivasan (2008) recorded five plant parameters, i.e., pod length,

width, trichome density, thickness and toughness, in nineteen selected genotypes of

field bean which influenced the incidence of pod borer complex, Helicoverpa armigera

(Hubner), Maruca vitrata (Geyer) and Exelastis atomosa (Walsingham). Based on field

incidence in Tirupati (Andhra Pradesh, India) during 2005-06, HA-4 (white) was

identified as a resistant genotype. Pod length and pod width were the least (4.51 and

0.75 cm, respectively) in HA-4 genotype. The susceptible cultivar (USA GP 36 (12-1)

FB KO2) had the least number of trichomes on pod (9-10 mm2). Rind thickness and pod

toughness showed a negative correlation with pod damage. The susceptible genotype,

GA 2-27, possessed lower rind thickness (0.72 mm) and pod toughness (0.75 kg cm-2)

compared to the resistant genotype HA-4 (1.42 mm and 0.85 kg cm-2, respectively).

Sunitha et al. (2008 a) have studied the association of different morphological

traits with resistance/susceptibility to M. vitrata. Trichome length and density were

found to be associated with resistance to M. vitrata in short-duration pigeonpea

genotypes and ICPL 98003 and ICPL 98008 was categorized as highly resistant and

ICPL 98012 as moderately resistant.

Jaydeep Halder and Srinivasan (2011) have recorded eight plant parameters, viz.,

pod wall thickness, number of pods/cluster, angle between the pods, trichomes on

leaves and stems, trichome length, pod length and pod width in relation to the

expression of varietal reaction towards, Maruca vitrata in eleven genotypes of cowpea

and observed that highly susceptible genotype GC-9708 had least number of trichomes

on stems (5.1) and leaves (4.8) as compared to highly tolerant genotype HC-270 which

had 7.5 and 9.4 trichomes/mm2, respectively. Pod wall thickness, angle between the

pods and pod width showed a negative correlation with pod damage. Highly susceptible

genotype GC-9708 possessed lowest pod wall thickness (0.77 mm), least pod width

(6.35 mm) and minimum pod angle (40 degrees) as compared to most tolerant genotype

HC-270 (0,89 mm, 7.80 mm & 85 degrees, respectively). Similarly, highest pod length

(15.55 cm) and maximum number of pods/cluster (2.8) were recorded from GC-9708 as

compared to others.

2.3.2 Biochemical Characters

Oghiakhe et al. (1993 a) have demonstrated the biochemical basis of resistance

of Vigna vexillata (Acc. TVNu 72) to M. vitrata and observed that the total sugar

content in the pod wall and seed of TVNu 72 was higher (P <0.05) than in IT82D-716.

Phenol content was lower (P <0.05) in the pod wall of TVNu 72, but the reverse was

true for fresh and dry seeds. This suggested that neither phenol nor total sugar was

involved in the resistance of TVNu 72 to M. vitrata.

Oghiakhe et al. (1993 a) have studied the relationship between the concentration

of phenol in cowpea and field resistance to the M. vitrata and observed that phenol does

not play any significant role in cowpea resistance to M. vitrata.

Prasad et al. (1996) have recorded the biochemical characters viz., total tannin,

phenolic and protein contents of the seeds of six cowpea genotypes that confers

resistance to Maruca vitrata and observed that they were in the range of 0.11-0.95,

0.01-0.05 and 17.41-19.60% of defatted meal, respectively. Variation in enzyme

inhibitory activity was correlated with degree of field pest resistance. The highest

trypsin inhibitor and chymotrypsin inhibitor activities were in GC82-7.

Veeranna (1998) has studied the two biochemical parameters in 45 cowpea

(Vigna unguiculata) genotypes for the resistant/susceptible to Maruca

vitrata infestation and observed that the resistant genotypes had higher phenol and

tannin contents than in susceptible genotypes.

Machuka (1999) has recorded the 25 lectins from 15 plant families on the

development of spotted pod borer (MPB) larvae. The list included 8 galactose/N-

acetylgalactosamine, 7 mannose, 5 complex glycan, 2 salicylic acid and

3, N-acetylglucosamine-specific lectins. Although a total of 16 lectins had detrimental

effects pertaining either to larval survival, weight, feeding inhibition, pupation, adult

emergence and/or fecundity, only the Listera ovata agglutinin (LOA) (Orchidaceae)

and Galanthus nivalis (Amaryllidaceae) agglutinin were effective against MPB larvae

for all six parameters examined. Larval mortality and feeding inhibition caused by the

most active lectin (LOA) was above 60%.

Chandrayudu et al. (2006) have demonstrated the incidence of M. vitrata in field

bean, cowpea, pigeon pea, mung bean and urd bean in relation to plant chemical

characters, i.e. total phenols in pods and total N in pods and found that cowpea and field

bean were the most preferred hosts of M. vitrata.

Jaydeep Halder et al. (2006) have studied the 6 biochemical parameters, i.e.,

total sugar, reducing sugar, non-reducing sugar, amino acids, proteins and phenols in

pods in relation to the expression of varietal reaction towards the spotted pod

borer Maruca vitrata in 10 mung bean cultivars (LGG-450, LGG-460, LGG-492, LGG-

485, LGG-483, LGG-489, LGG-407, LGG-523, MGG-348 and LGG-497), conducted

in Andhra Pradesh, India, during the 2003/04 rabi season, and observed that the highly

susceptible cultivar LGG-450 had highest amount of total sugar, reducing sugar, non-

reducing sugar, amino acids and protein (1.38 mg/g, 0.59 mg/g, 0.79 mg/g, 0.130% and

23.44%, respectively) compared to the highly tolerant cultivar LGG-497 which had

1.13 mg/g, 0.48 mg/g, 0.65 mg/g, 0.072% and 18.56% respectively, whereas phenols

were highest in the resistant cultivar LGG-497 (21.03 mg/g) than the susceptible

cultivar LGG-450 (20.00 mg/g). A significant and positive correlation existed between

total sugar, reducing sugar, non reducing sugar, amino acids and proteins with pod

damage, whereas negative correlation existed between phenol contents in pods with pod

damage.

Halder and Srinivasan (2007) recorded the six biochemical parameters, viz.,

total sugar, reducing sugar, nonreducing sugar, amino acids, proteins and phenols in

pods, in relation to the expression of varietal reaction to Maruca vitrata in urd bean

(Vigna mungo) genotypes LBG-17, LBG-22, LBG-623, LBG-402, LBG-20, T-9,

LBG-685, PBG-1, PBG-107 and LBG-611. The highly susceptible cultivar LBG-17 had

the highest amount of total sugar (1.42 mg/g), reducing sugar (0.62 mg/g), nonreducing

sugar (0.80 mg/g), amino acids (0.13%) and protein (24.3%) and the lowest values were

recorded in the highly tolerant cultivar LBG-611 which had 1.2 mg/g, 0.50 mg/g, 0.70

mg/g, 0.07% and 21.6%, respectively. Phenols were highest (21.72 mg/g) in the

resistant cultivar LBG-611 than the susceptible cultivar LBG-17 (20.41 mg/g). There

was a significant and positive correlation existing between total sugar, reducing sugar,

nonreducing sugar, amino acids and proteins with pod damage whereas negative

correlation prevailed between phenols contents in pod with pod damage.

Resistance to spotted pod borer (Maruca vitrata) and blister beetle

(Mylabris spp.) was evaluated in 12 hybrids and 7 parental genotypes of pigeon pea and

observed that the highest grain yield and lowest yield loss were recorded for LRG 41

and among the hybrids, LRG 41 x ICPL 87119 registered the highest yield and lowest

yield loss. Resistance to both pests appeared to be due to low total free amino acid

content and crude protein content, and high levels of total phenolics in pigeonpea

genotypes (Anantharaju and Muthiah, 2008).

Sunitha et al. (2008 a) have demonstrated the association of different chemical

traits with resistance/susceptibility to M. vitrata. Sugars, proteins and phenols were

found to be associated with resistance to M. vitrata in short-duration pigeonpea

genotypes and ICPL 98003 and ICPL 98008 was categorized as highly resistant and

ICPL 98012 as moderately resistant.

Sujithra and Srinivasan (2012) studied the biochemical characters in 84

genotypes of fieldbean that confers resistance to M.vitrata and observed that highly

susceptible cultivar AVT-FB(80) 15-6-4 had highest amount of protein (28.9%),

reducing sugar (1.72 %) as compared to tolerant cultivar TCR-137 which had 19, 1.05

% of proteins and reducing sugars, respectively. A significant positive correlation were

existed between protein and reducing sugars with pod damage whereas negative

correlation prevailed between silica and crude fibre contents with pod damage.

2.4 BIOLOGY OF SPOTTED POD BORER ON VARIOUS PULSE CROPS

INCLUDING BLACKGRAM AND GREENGRAM

Observations on the biology of spotted pod borer, M.testulalis were first made

by Dietz in 1914 on cowpea and greengram in east coast of Sumathra (Indonesia).

Taylor (1967), presented a detailed account of the bionomics of the spotted pod

borer, M.testulalis in northern Nigeria on cowpea.

Ramasubramanian and Babu (1988) demonstrated the effects of 3 host plants

viz., pigeon pea, cowpea and hyacinth bean on various biological parameters of the

M. testulalis in the laboratory to enable the selection of a suitable host plant for mass

rearing and observed that the number of eggs laid by females and percentage

hatchability were highest on hyacinth bean. The total larval duration was 13.32, 13.86

and 12.90 days when reared on pigeon pea, cowpea and hyacinth bean, respectively.

The larvae reared on hyacinth bean produced the heaviest pupae (39.94 mg) with the

longest pupal period (7.48 days). The pre-oviposition period was significantly longer on

hyacinth bean (2.7 days). The oviposition period of females was longer on hyacinth

bean and pigeon pea (both 3.90 days) than on cowpea (3.60 days). The longevity of

adults was increased by rearing larvae on hyacinth bean. It is concluded that hyacinth

bean is more suitable for the mass rearing of M. testulalis.

Ramasubramanian and Babu (1989) recorded the biology of

the M. testulalis on 3 leguminous food plants in the laboratory at 24-270 C and

observed that the egg period averaged 2.9-3.1 days on all 3 plants, while the larval

period was 12.9, 13.32 and 13.86 days on hyacinth bean, pigeonpea and cowpea. The

prepupal periods were 1.46, 1.52 and 1.8 days, and the pupal period was 6.36 days on

pigeonpea and 6.9 and 7.48 days on cowpea and hyacinth bean, resp. The adult lifespan

averaged 5.9-6.1 days for males and 8.5-10 days for females. Fecundity averaged 35.3,

37.6 and 38.30 eggs/female on pigeonpea, cowpea and hyacinth bean, respectively.

The growth index was 5.17 on hyacinth bean, 4.63 on cowpea and 4.14 on pigeonpea.

Hyacinth bean was the most favourable food plant and pigeonpea the least.

Ramasubramanian and Babu (1989 a) observed that the number of eggs laid per

female in the first 5 days after mating averaged 12.20, 15.91 and 19.31 on pigeon pea,

cowpea and hyacinth bean, respectively by recording the ovipositional preference by

M.testulalis on susceptible cultivars of 3 leguminous food plants in the laboratory.

Echendu and Akingbohungbe (1990) demonstrated the free-choice and no-

choice cohort tests on 4 cowpea varieties earlier identified from field screening trials as

resistant (TVU 946, TVU 1896 AG, H 51-1 and 2 AK) and 3 susceptible genotypes (Ife

Brown, H 144-1 and 58-185) and observed that the non-preference for oviposition and

larval feeding, and antibiosis manifested by reduced final-instar larval weight,

lengthened pupal period and small-sized emerging adult females in resistant genotypes.

Oghiakhe et al. (1993 b) have reported that the mean pupal weight ranged from

43.5 to 54.5 mg on floral buds, 38.5 to 58.6 mg on flowers and 42.7 to 58.6 mg on

sliced pods, with highly significant differences (P <0.01) between resistant and

susceptible cultivars on each part by studying the biology of M. vitrata on different

parts of 18 cowpea cultivars. Growth indices showed that sliced pods were the most

suitable for larval growth and development, followed by flowers and floral buds. The

levels of resistance found were inadequate for solving the M. vitrata problem in

cowpea.

Veeranna et al. (1999) have observed that the incubation period, larval (5

instars), pre-pupal and pupal periods, total life cycle of M. testulalis were on average

2.95, 11.07, 2.30, 8.50 and 24.92 days, respectively under laboratory conditions at a

temperature of 20-350 C at a relative humidity of 50-80% by maintaining individuals on

young shoots, flower buds and flowers of cowpeas.

Sharma and Franzmann (2000) reported that the post-embryonic development

was completed in 20.2 to 22.6 days by studying the biology of the legume pod borer,

Maruca vitrata (Fabricius) on pigeonpea (Cajanus cajan) and Adzuki bean (Phaseolus

angularis [Vigna angularis]).

Huang ChiChung and Peng WuKang (2001) recorded the emergence, mating

and oviposition of bean pod borers (M. vitrata) in the laboratory and observed that the

adults emerged throughout the day, but however, approximately 55% of females and

31% of males emerged at night. The emergence peaked at 03.00-05.00 and 13.00-15.00

h for females and males, respectively. The sex ratio was 0.49. The premating,

preoviposition and oviposition periods of the female were 3.8, 4.5 and 3.4 days,

respectively. The highest mating frequency occurred in 3-day-old females. The adults

started to mate at 21.00 h. The mating time lasted for 44.4 ± 34.3 minutes. A female

deposited 11.2 ± 9.7 eggs per day, and laid 67 eggs in her lifespan. The longevity of

female and male adults averaged 9.0 ± 2.6 and 7.9 ± 2.0 days, respectively.

Chinnabhai et al. (2002) have studied the biology of spotted pod borer M. vitrata

under laboratory conditions on blackgram and greengram during 2000-01 and reported

that the pre-oviposition, oviposition, post oviposition, incubation, larval (five instars)

and pupal periods, adult longevity of male and female, sex ratio (male:female),

fecundity and total life cycle recorded were 1.56, 3.53, 1.03, 3.03, 10.35, 6.02, 4.77 and

6.09 days, 1:1.3, 60.48 eggs/day/female and 25.38 days, respectively on black gram;

and 1.71, 3.53, 1.71, 3.14, 11.12, 6.56, 5.67 and 6.77 days, 1:1.3, 55.45 eggs/day/female

and 26.78 days, respectively on green gram.

Chandrayudu et al. (2005) have recorded the biology of M. vitrata on five

legumes, i.e., cowpea, field bean, pigeon pea, mung bean and urd bean, under

laboratory conditions during 2002-03 and observed that fresh eggs were milky white

and oval in outline and the fecundity of female moth ranged between 109.2 and 174.2 in

different hosts. The average incubation period, larval period and period for completing

total life cycle ranged from 3.16 to 3.86, 9.24 to 11.65 days, and 23.10 to 24.94 days on

five, respectively. The total cycle was shortest and fastest on cowpea, and hence it was

the most preferred host.

Bhagwat et al. (2006) reared the larvae of M. vitrata on leaves, flowers and

pods of 9 short-duration pigeon pea genotypes (MPG 537, MPG 537-M1-2-M5, ICPL

90011, ICPL 84023, ICPL 88034, ICPL 4, MPG 664-M1-2-M20, ICPL 90036-M1-20

and ICPL 87) under laboratory conditions to study the suitability of different genotypes

for survival, growth, pupation and fecundity of this insect and observed that on an

average, 50-94% and 57-97% of the larvae completed their development on flowers and

on pods. Larval survival and pupation were the greatest on cowpea leaves. The insects

reared on pods had higher and shorter larval, and adult developmental periods than on

flowers or leaves. The larvae reared on leaves exhibited low larval and pupal weights,

longer larval developmental time, higher pupal and shorter adult life span. Larvae

reared on ICPL 84023 had the lowest larval and pupal weights and longest pupal and

adult developmental time compared to other cultivars. The adult female whose larvae

reared on flowers produced more eggs than those reared on pods. However, egg

hatching was greater in the eggs of the moths whose larvae were reared on pods than

flowers. Moths emerged from the flower and pod of ICPL 90036-M1-2 produced the

highest number of eggs followed by ICPL 90011 and MPG 537-M1-2-M5.

Ghorpade et al. (2006) studied the biology of M. vitrata on pigeon pea (cv.

ICPL-87) in the laboratory,and observed that the eggs were laid singly or in cluster of

2-12 on tender leaves, buds, flowers, tender pods and stems. The lower leaf surface was

the most preferred site for oviposition. A single female laid 58 eggs, on average. The

1st, 2nd, 3rd, 4th and 5th larval, total larval, pre-pupal and pupal periods lasted 3.43,

2.5, 2.42, 2.33, 4.25,13 to 17, 1.1 and 7.6 days on average, respectively. The entire life

cycle was completed in 26-45 days (35.1 days on average).

Panickar and Jhala (2007) studied the comparative biology of spotted pod borer

controlled temperature of 27 ± 1o C and observed the shorter period (days) of egg

(2.32), 1st (2.30), 2nd (2.56), 3rd (2.75), 4th (2.75), 5th (2.60) instar larva; significantly

shorter total larval (13.71 days), pre-pupal (1.59 days), pupal (5.36 days) and pre-

oviposition (1.10 days) periods; significantly longer oviposition periods (4.30 days) in

the female and adult period (6.40 days) of male; significantly shorter total life cycle

(29.36 days) of female and significantly higher fecundity (41.80 eggs) and growth

index (5.71) were recorded in the culture of M. vitrata reared on cowpea compared to

green gram, black gram, pigeon pea and Indian bean. Cowpea was the most preferred

host for growth and development of M. vitrata.

Shukla et al. (2008) studied the biology of the spotted pod borer, M. vitrata, on

cowpea and observed that the larvae passed through five instars and larval development

occurred in an average duration of 14.1 days. The pupal stage lasted for an average of

7.53 days and the total life cycle occupied 26.77 days in males and 30.42 days in

females. A female laid an average of 49.37 eggs, ranging from 23 to 78 and the average

hatchability was 81.53 per cent. Among the six hosts evaluated, the larvae preferred

cowpea as evidenced from higher pod damage than green gram, black gram, pigeon

pea, Indian bean and moth bean.

Naveen et al. (2009) studied the biology of Maruca vitrata, and observed that

eggs were laid on the under surface of leaves, terminal shoots and flower buds. The

freshly laid eggs were milky white in colour and oval in outline, dorsoventraly flattened

and glued to the surface. The incubation, first, second, third, fourth and fifth instar

larval, pre-pupal and pupal period, total developmental, pre-mating, pre-oviposition and

oviposition period varied from 2.54 ± 0.04, 1.28 ± 0.07, 1.35 ± 0.10, 1.50 ± 0.05,

2.08 ± 0.16 and 3.50 ± 0.25, 2.10 ± 0.50 and 8.00 ± 0.85, 22.36 ± 1.45, 3.22 ± 0.84,

1.34 ± 0.36 and 4.60 ± 3.45 days. Fecundity was 126.8 ± 103.2 eggs per female

whereas viability of eggs was 95.45 ± 2.54%.

Zhao Sheng et al. (2009) studied the biology of M. testulalis and observed that

the insect produced 4-5 generations per year and overwintered as pupa. On average, one

individual consumed approximately 34.36 mg bean (Dolichos lablab) pods at the larval

stage. The percentages of the 1st, 2nd, 3rd, 4th and 5th larval instars on fallen flowers

in the field were 51.23, 18.83, 19.44, 6.79 and 3.70%, respectively. The weight, length

and width of the pupa were 0.04 ± 0.01 g, 11.13 ± 0.45 mm and 2.84 ± 0.13 mm,

respectively. Female and male longevity reached 6.00 ± 1.22 and 5.58 ± 0.59 days,

respectively. The female to male ratio was 1:0.54.

Sonune et al. (2010) carried out bionomics of M. testulalis (Geyer) under the

laboratory conditions at an average temperature of 26.50 C and 83.50 per cent relative

humidity and observed that the female moth laid eggs on the flower buds and flower

surface or inner surface of glass jar. The mean incubation, first, second, third, fourth

and fifth instar larval, mean total larval, pupal periods, longevity of female and male

moth, preoviposition, oviposition and post oviposition periods was 3.24 ± 0.72, 2.12 ±

0.66, 2.80 ± 0.70, 2.76 ± 0.66, 2.76 ± 0.72 and 3.60 ± 0.64, 14.04 ± 0.97, 10.84 ± 1.79,

8.06 ± 1.90 and 6.24 ± 1.33, 1.76 ± 0.72, 3.8 ± 0.79 and 2.84 ± 0.80 days . The adult

moth had medium brown wings and creamy white to brown body with long legs. The

total number of eggs laid by a single female was on an average of 38.8 ± 3.85 eggs. The

total life cycle from egg to emergence of adult was completed within 26.25 ± 1.44 days

and 32.04 ± 2.97 days by male and female respectively.

Chaitanya et al. (2012) studied the biology of legume pod borer, Maruca

vitrata (G.) on pigeonpea at S. V. Agricultural College, Tirupati during 2011-12 and

observed that the mean longevity of the adult was 8.83 ± 0.82 days. There were five

larval instars which took 9.52 ± 0.71 days to enter into pupal stage. Pupation took place

in the webbed flowers/pods and the pupal period lasted for about 7.25 ± 0.82 days. The

life cycle of M. vitrata was completed in 22.13 ± 1.25 days.

2.5 INSECTICIDE TOLERANCE

2.5.1 Plant Resistance and Insecticides Interaction - Synergistic

2.5.1.1 Antixenosis and chemical control

Plant resistance, involving morphological characteristics like long peduncles and

erect pods of cowpea (Singh, 1978), frego-bract in cotton (Niles, 1980) etc., may

facilitate better coverage of insecticides leading to increased pest mortality. When

sprayed with methyl-parathion, frego-bract buds had seven times greater deposit of

insecticide than normal bract buds.

2.5.1.2 Antibiosis and chemical control

Painter (1951) mentioned that the main advantage of growing partially resistant

varieties (with an antibiosis type of resistance) was to impose a constant level of

suppression on the insect population at each generation. This would result in a

decreased pest population over subsequent years, lowering the requirement for chemical

control.

Insects on resistant plants tend to be smaller than insects on susceptible plants,

due to the stress imposed on them by these plants by either physical or chemical means.

As the toxicity of an insecticide depends on the body weight, lower amounts of

insecticide should be required to get the same mortality on resistant plants as that of

susceptible plants (Van Emden, 1991).

Nymphs of the wheat grain aphid, Sitobion avenae (F.) reared on the resistant

wheat variety ‘Altar’ possessing the antibiosis compound DIMBOA were more

susceptible to deltamethrin than nymphs on the susceptible wheat variety ‘Dollarbird’.

The LD50 adjusted for weight was reduced by 91% for nymphs reared on the resistant

cultivar (Nicol et al., 1993).

2.5.1.3 Moderate levels of plant resistance and chemical control

Even with only moderate to low levels of plant resistance, it should often be

possible to reduce insecticide concentration to one-third of that required on a

susceptible variety (Van Emden, 1990).

Several people working with plant resistance, particularly with sucking insects,

have confirmed that lower LC50 and LD50 values are obtained for insects reared on

partially resistant than on susceptible plant varieties (Selander et al., 1972; Muid, 1977;

Attah, 1984).

Muid (1977) compared the susceptibility of an organophosphate resistant strain

of the aphid, M.persicae on two varieties of Brussels sprouts and observed that the

aphids were more susceptible to the chemical on the moderately resistant Brussels

sprout than on the susceptible Brussels sprout.

Heinrichs et al., (1984) showed that the LD50 (µg/g) of whitebacked plant

hopper was 9.4 on the susceptible variety ‘TN1’ treated with ethylan, but was only 2.8

on the moderately resistant variety ‘N22’.

2.5.2 Plant Resistance and Insecticides Interaction – Antagonistic

Resistant genotypes of many crop varieties presently grown world-wide owe

their resistance to the presence of deterrent or toxic allelochemicals (Painter, 1951;

Norris and Kogan, 1980). Examples are 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-

one (DIMBOA) in varieties of corn resistant to the corn borer, Ostrinia nubilalis

(Hubner) (Klun et al., 1967), gossypol in cotton varieties resistant to the bollworm,

Heliothis spp (Niles, 1980) and 2-tridecanone in glandular trichomes of tomato resistant

to Manduca sexta (Kennedy et al., 1987).

There have been several other reports of increase in tolerance of insecticides in

insects cultured on plants having allelochemicals owing to the induction of detoxifying

enzymes (Kennedy et al., 1987 a).

In insects, detoxifying enzymes that are responsible for metabolizing the toxic

plant allelochemicals can also be responsible for metabolizing the synthetic

insecticides. This could lead to an increase in tolerance levels to insecticides in insects

feeding on resistant plants. Increased resistance of Heliothis virescenes (F.) to methyl-

parathion was found to be associated with gossypol in cotton (Shaver and

Wolfenbarger, 1976).

Plant resistance can either increase (synergistic effect) (Kea et al. 1978; Rose et

al. 1988; Panda et al. 2006) or decrease (antagonistic effect) (Wieb and Radcliffe 1973;

Carter 1987; Kennedy et al., 1987) the susceptibility of a given insect population to an

insecticide.

Raman (1988) found no significant effect on insecticide tolerance levels when

the green peach aphid (Myzus persicae Sulzer) fed on host plants with different degrees

of resistance.

Brassica cultivars with varying degrees of partial plant resistance were fed to

larvae (up to 4th instar) of the diamondback moth (DBM), Plutella xylostella, and were

bioassayed by topical application of cypermethrin to investigate the interaction of plant

resistance with insecticide. Larvae reared on the least preferred brassica, Minicole,

showed a significantly higher LD50 value than those on the most preferred brassica,

Chinese cabbage. Bioassay of 4th instar DBM larvae fed on artificial diet containing

pure compounds of glucosinolates revealed a negative interaction between their

susceptibility to cypermethin and certain glucosinolates (in particular sinigrin),

suggesting that such compounds induced the production of insecticide-detoxifying

enzymes (Karnam and Van Emden, 2014).

Chapter III

MATERIALS AND METHODS

The present investigations on the “Influence of plant resistance in certain

genotypes of blackgram and greengram on insecticide tolerance on Maruca vitrata

(Geyer)” were carried out during the year 2014-15. The laboratory experiments and

field experiments were carried out in the Department of Entomology, Sri

Venkateswara Agricultural College and Regional Agricultural Research Station,

Tirupati, Andhra Pradesh. Material and methods employed for these studies are

presented in this chapter.

3.1 SURVEY ON INCIDENCE OF M. vitrata IN BLACKGRAM AND

GREENGRAM AND INSECTICIDE USAGE IN MAJOR GROWING

AREAS OF SOUTHERN ZONE OF ANDHRA PRADESH DURING

LATE KHARIF 2014.

Survey on M.vitrata population in blackgram and greengram during late

kharif 2014 was carried out in Chittoor, Nellore and Kadapa districts. Roving

survey was conducted and data on number of plants infested with spotted pod borer

was recorded in 1 sq.mt area, to calculate the per cent damage. In each infested

plant, total number of webbings were recorded. During the survey, insect

infestation was recorded at different crop stages such as vegetative, flowering, pod

formation and pod maturation.

Information on name of the varieties of blackgram and greengram, number of

sprays, dosage and group of insecticides used was collected from 5 progressive

farmers in each village. A total of 3 villages in each mandal was selected for the

survey. Thus a total of 27 samples were collected from 27 villages of 3 districts.

Information was collected by using the following proforma.

Proforma for Survey on Spotted Pod Borer Incidence in BLACKGRAM and GREENGRAM

Insect damage at various crop growth stages Insecticide

sprayed Dosage

How many

times applied

during that

particular stage

Fungicide

sprayed

Natural

enemies

noticed

Approximate

Date of

Harvest

(Days)

Yield

(Q/acre)

Any

additional

information

(%

incidence)

(n) (o) (p) (q) (r) (s) (t) (u) (v)

Vegetative Flowering Pod

formation

Pod

maturation

Date

of

visit

Name of the

farmer

Name of the

village /

mandal

Total

land

holding

(owned or

leased)

cultivated

area

(acres)

Date of

sowing

Variety Whether

seed

treatment

is followed

or not

Seed

rate (kg

per

acre)

Spacing

(cm)

Method

of

sowing

Fertilizers

applied

(Kg/acre)

Herbicides

applied /

manual

weeding

(a) (b) (c) (d) (e) (f) (g) (h) (i) (j) (k) (l) (m)

3.2 SCREENING FOR THE INCIDENCE OF M.vitrata ON DIFFERENT

GENOTYPES OF BLACKGRAM AND GREENGRAM

A screening trial was laid out with nine genotypes of blackgram and ten

genotypes of greengram against the spotted pod borer (M.vitrata) in the wetland

farm, S.V. Agricultural College, Tirupati during August, 2014. The experimental

location was situated at an altitude of 182.9 m above MSL on 79°36N latitude and

13o37E longitude in the Southern Agro Ecological Zone of Andhra Pradesh. The

experiment was laid out in a randomized block design with three replications of

blackgram and six replications of greengram.

The experimental material comprised of nine genotypes of blackgram (LBG-

685, PU-31, LBG-20, LBG-790, LBG-752, LBG-792, LBG-123, LBG-791, LBG-

645) and ten genotypes of greengram (WGG-42, LGG-407, PM-115, MGG-360,

PM-110, LGG-410, PM-112, TM-962, LGG-450, LGG-460) of diverse origin,

which was procured from LAM farm, Guntur and R.A.R.S, Tirupati. Each genotype

was sown in single row of 2m length with the spacing of 30 cm between the rows

and 10 cm within the row. Likewise, three replications of nine genotypes of

blackgram and ten genotypes of greengram were sown There were two different

dates of sowing (first sowing during last week of August-2014 of both blackgram

and greengram and second sowing of greengram was done in second week of

September-2014). The crop was raised following all the recommended agronomic

practices and kept free from insecticidal sprays .

During the period of study, incidence of the spotted pod borer across

different genotypes was recorded from vegetative parts, flower buds and pods. Five

randomly selected plants were tagged in each genotype for long term sampling to

record the infestation of the spotted pod borer.

3.2.1 Incidence of Spotted Pod Borer In Different Genotypes of Blackgram

and Greengram

Nine genotypes of blackgram that were raised with three replications and

one date of sowing and ten greengram genotypes that were raised with six

replications and two dates of sowing were evaluated against incidence of spotted

pod borer. Observations for the initiation of infestation of the spotted pod borer on

vegetative parts, flower buds and pods were recorded for each genotype with

destructive sampling of webbings, at weekly intervals. The data was recorded on

total number of plants in each test genotype and number of plants infested with

M.vitrata, number of webbings and larva from five tagged plants in each test

genotype and data were expressed as the per cent damage and incidence of insect

pest on vegetative parts, flower buds and pods etc., Data was analysed by using the

SPSS (2004). Based on the observations, the genotypes were grouped into resistant,

moderate resistant and susceptible to their reaction to Maruca infestation and were

used for further investigations.

3.3 MAINTENANCE OF NUCLEUS CULTURE OF SPOTTED POD BORER

The nucleus culture of spotted pod borer was maintained in laboratory, at the

Department of Entomology, S.V. Agricultural College, Tirupati. Initially large

number of larvae of specific instar were collected from the crop cafeteria of dryland

farm, S.V. Agricultural College and also from the research fields of R.A.R.S,

Tirupati. Initially these larvae were kept in masses in translucent rearing plastic trays

of size 32 cms diameter and 9.8 cms depth. Since these larvae exhibited cannabalism

they were separated and kept in gram pod borer rearing plastic boxes of size 34 cms

length on all sides and locule of depth 5.5 cms and in six well cell culture clusters of

size 12 cms length and 8.5 cms width (3.7 cms diameter of each locule) individually

and fed with flowers of soyabean crop, leaves, pods. The food was changed at every

two days and the rearing boxes were cleaned with 10 percentage formalin to prevent

fungal contamination. Fresh feed was provided to M.vitrata collected from the

soyabean crop which was raised for the maintenance of further generations of

spotted pod borer. The pupae were not disturbed till they attain the brown colour

from green colour. These pupae were separated carefully with the help of camel hair

brush and kept individually in adult oviposition boxes of size 30×30×30 cm having

aeration at both sides. Cotton swab dipped in 10 per cent sucrose solution was kept

as food for emerging adults (Plate 3.1). The relative humidity and temperature was

maintained at 85 ± 5% and 24̊ ± 20C respectively during the entire rearing process.

For oviposition purpose, redgram apical branches having flower buds, tender leaves

and freshly formed tender pods were provided in a conical flask with sucrose

solution to keep the twigs fresh for four to five days. Eggs that were laid on these

material were separated with a brush and were kept in plastic trays for emergence of

first instar larvae. First instar larvae were separated carefully with camel hair brush

and placed in trays having flower buds. For first and second instar larvae, only

flower buds and for third, fourth and fifth instar larvae, flowers, leaves and pods

were kept for feeding, first instar larvae of M.vitrata from nucleus culture was used

in all the subsequent experiments on mechanisms of resistance in selected

blackgram and greengram genotypes to Maruca infestation.

3.4 TO STUDY THE MECHANISMS OF RESISTANCE IN SELECTED

GENOTYPES OF BLACKGRAM AND GREENGRAM

The genotypes of blackgram and greengram that were grouped into resistant,

moderate resistant and susceptible to Maruca damage from field observation, were

used in the present study to confirm their resistant rankings.

3.4.1 Feeding Preference In Free-Choice Technique

The leaves, flowers, and developed pods of resistant, moderate resistant and

susceptible genotypes of blackgram and greengram were placed in a radical fashion

in separate petriplates of size 18cm diameter, at equal distance. Six larvae of same

instar were released in the middle of the petriplate and after 24 hours, larvae on each

test genotype was recorded to test feeding preference.

3.4.2 Feeding Preference In No Choice Technique (Biology of M.vitrata)

Six first instar larvae were released separately for each test genotype of

blackgram and greengram in six loculed cell wells and observations were recorded

on biological parameters such as duration of egg stage, instar durations, pre-pupal

duration, pupal duration, adult longevity, sex ratio etc., of the spotted pod borer.

3.4.2.1 Larval stage:

From the day of hatching of the egg, the first and second instar larvae of

spotted pod borer were provided with sufficient amount of flower buds of resistant,

moderate resistant and susceptible genotypes of blackgram and greengram for

feeding. For third, fourth and fifth instar larvae, flower buds and developed pods

were provided for feeding. The time from hatching of first instar to the final

pre-pupal stage were considered as the total larval duration. Duration of each instars

of larvae was recorded by observing the moulted skins of the next larval stages on

test genotypes of blackgram and greengram.

3.4.2.2 Pupal stage:

The duration of pupation to the adult emergence was considered as the

duration of pupal stage of the moth and was expressed in days.

3.4.2.3 Adult stage:

From the day of adult emergence till the death was considered as the adult

longevity. Other parameters such as male:female ratio, pre-oviposition periods,

oviposition periods, post-oviposition periods and fecundity were also recorded.

3.5 STUDIES ON BIOPHYSICAL AND BIOCHEMICAL CONSTITUENTS

OF SELECTED BLACKGRAM AND GREENGRAM GENOTYPES

Data was recorded on the selected genotypes on morphological characters such as

plant height, trichome density etc., and biochemical constituents such as phenols, proteins

and total reducing sugars of selected genotypes were estimated at Institute of Frontier

Technology, R.A.R.S, Tirupati.

3.5.1 Morphological (Biophysical) Characters

The blackgram and greengram genotypes that were selected as resistant,

moderately resistant and susceptible to spotted pod borer from field observations

were analyzed for biophysical characters of the vegetative and flowering parts to

correlate the chatacters to the incidence of Maruca damage.

3.5.1.1 Plant height

The plant height of blackgram and greengram genotypes were collected

randomly from each genotype and the height was measured with the help of

measuring scale and expressed in centimeter.

3.5.1.2 Trichome density

The trichome density was measured on the adaxial surfaces of the leaves of

selected blackgram and greengram genotypes. The leaf was cut into 0.25 cm2 area

and the number of trichomes present were counted and expressed as number of

trichomes per 0.25 cm2.

3.5.1.3 Measurement of chlorophyll content of leaves:

The chlorophyll content of leaves were measured using the Chlorophyll

meter SPAD 502 and expressed in SCMR units. 3rd opened leaves of each genotype

of blackgram and greengram were used for estimating the chlorophyll content.

3.5.2 Biochemical Constituents

The blackgram and greengram cultivars were subjected for analysis of

biochemical components in the pod walls viz., proteins, phenols and reducing

sugars. Each sample was divided into three sub samples and mean contents of the

biochemicals in respective genotypes were recorded.

3.5.2.1 Estimation of protein by Lowry’s method

Estimation of protein content in pod walls of blackgram and greengram

genotypes was done as per the method developed by Lowry et al. (1951).

Preparation of reagents

a) Reagent-A: Reagent A was prepared by mixing sodium carbonate 2.0 per

cent and sodium hydroxide 0.1 N with each other.

b) Reagent-B: Reagent B was prepared by mixing copper sulphate 0.5 per cent

(CuSO4 H2O) in 1.0 per cent sodium potassium tartarate.

c) 2 N sodium hydroxide: 8 g of sodium hydroxide was taken in a beaker and

made upto 100 ml with distilled water.

d) Reagent-C: Alkaline copper solution was prepared by mixing 50 ml of

reagent A and 1 ml of reagent B.

e) Reagent-D: Folin-ciocalteau reagent was mixed with distilled water at a

ratio of 1:1.

Preparation of working standard

Fifty milligrams of bovine serum albumin was dissolved in distilled water

and the final volume of stock solution was made upto 50 ml in a volumetric flask.

From this, 10 ml was taken in another standard flask and volume was made upto 50

ml. From the working standard, solutions of different concentrations of protein were

prepared.

Procedure

A sample of 500 mg was weighed and ground in pestle and mortar with 5 ml

of 10 per cent trichloro acetic acid (TCA). The ground material was washed with 5

ml of cold TCA and kept in ice for 15 min. The material was centrifuged at 3500

rpm for 15 min and the supernatant was discarded and the precipitate was dissolved

in 4 ml of 2 N NaOH. It was allowed to stand for overnight. Then it was centrifuged

and supernatant was collected and finally the aliquot was made upto 10 ml.

From this aliquot, 0.1 ml of sample extract was pipetted out, to which 5 ml of

reagent-C was added. The contents were mixed well and allowed to stand for 10

min. Afterwards 0.5 ml of reagent-D was added, mixed well and incubated for 30

min at room temperature in dark. The colour intensity was read at 660 nm.

Calculation

From the standard curve, concentration of protein expressed as per cent in

different entries were estimated.

3.5.2.2 Estimation of phenols

The phenol content in pod walls of blackgram and greengram genotypes

were estimated as per the method presented by Malick and Singh (1980).

Principle

Phenols react with phosphomolybdic acid in Folin-ciocalteau reagent in

alkaline medium and produce blue coloured complex (Molybdenum blue).

Preparation of reagents

Ethanol 80.0 per cent was prepared by adding 80 ml of absolute alcohol in a

beaker and made upto 100 ml by using distilled water.

Sodium carbonate 20.0 per cent was prepared by adding 20 g sodium

carbonate in 100 ml of distilled water.

Preparation of working standards

100 mg catechol dissolved in 100 ml of distilled water and diluted 10 times

for working standard, from the working standard different concentrations from 0.1 to

1.0 ml were taken.

Procedure

From each seed sample 0.5 g of material was weighed and ground in a pestle

and mortar, later added 10 times volume of 80.0 per cent ethanol. The homogenate

was centrifuged at 10,000 rpm for 20 min. The supernatant was collected and

residue was re-extracted with five times the volume of 80 per cent ethanol,

centrifuged and the supernatants were pooled and evaporated to dryness. The dry

residue was dissolved in 5 ml of distilled water and different aliquots 0.2 to 2.0 ml

was pipetted to test tubes, making the volume in each tube to 3 ml by adding

distilled water. Then 0.5 ml of Folin-ciocalteau reagent was added. After 3 min, 1

ml of 20.0 per cent sodium carbonate solution was added to each tube. The material

was mixed thoroughly and tubes were placed in boiling water exactly for 1 min. The

tubes were cooled and the absorbance was measured at 650 nm against a reagent

blank in spectrophotometer. The standard curve was prepared by using different

concentrations of catechol. Catechol concentrations on Y-axis and absorbance

values on X-axis were taken for standard curve preparations.

Calculation

From the standard curve, concentrations of phenols in terms of percentage

were expressed for the genotypes.

3.5.2.3 Estimation of reducing sugars

Reducing sugar content includes some of the reducing sugars like glucose,

galactose, lactose and maltose. The method by Somogyi (1952) was employed for

estimating reducing sugars.

Preparation of reagents

Reagent A was prepared by mixing 4 ml of copper sulphate solution (15 g of

CuSO4 dissolved in a small volume of distilled water and one drop of H2SO4 was

added then the volume was made up to 100ml) and 96 ml of alkaline copper tartarate

reagent (2.5 g anhydrous Na2CO3, 2 g of Na2HCO3, 2.5 g of potassium sodium

tartarate and 20 g of anhydrous sodium sulphate were dissolved in 80 ml water and

made upto 100 ml in a volumetric flask).Reagent B was prepared by dissolving 2.5 g

of ammonium molybdate in 45 ml of distilled water adding 2.5 ml H2SO4.Separately

0.3 g of disodium hydrogen arsenate (Na2HSO4. 7H2O) was dissolved in 25 ml

distilled water, and both solutions were mixed and placed in an incubator at 37°C

for 24 to 48 hours.

Preparation of working standards

100 mg of glucose was dissolved in 100 ml of distilled water in a volumetric

flask to prepare standard glucose stock. 10ml of stock was diluted to 100 ml. in a

volumetric flask to prepare working standard.

Procedure

100 mg of sample was weighed and grinded with mortar and pestle. Sugars

were extracted with 5 ml of hot 80 per cent ethanol twice. The extract was

centrifuged at 3500rpm for 10 minutes. Supernatant was collected and the ethanol

was evaporated by keeping the test tubes in a water bath at 80°C for 3 to 4 hrs.

Sugars collected at the base of the test tube were dissolved with 5 ml distilled water

and thoroughly mixed. Aliquots of 0.5 ml of sample were pipetted out in separate

test tubes and the volume was made up to 1 ml with distilled water. One ml of

reagent A was added to the sample and placed in boiling water bath for 10 minutes.

After cooling the test tubes, 1 ml of reagent B was added and the volume was made

up to 8 ml with distilled water.

Calculation

The absorbance of the solution was measured in a spectrophotometer at 620

nm. The amount of reducing sugars was estimated using a standard graph prepared

with glucose and expressed in percentage.

The spotted pod borer incidence was later correlated with the biophysical and

biochemical constituents of selected genotypes of blackgram and greengram.

3.6 TO STUDY THE EFFECT OF PLANT RESISTANCE IN SELECTED

GENOTYPES OF BLACKGRAM AND GREENGRAM TO M.vitrata

AND ITS ROLE IN INSECTICIDE TOLERANCE

3.6.1 Rearing of Maruca larvae

Based on field screening and biology studies in the laboratory, resistant, and

susceptible genotypes of blackgram and greengram were selected and were grown

in plastic pots of size 15 cm diameter and 15 cm depth in greenhouse with

staggered sowing. For the insecticide bioassay study, the first instar larvae from

nucleus culture were separated carefully with camel hair brush and were kept in

separate trays having flower buds of resistant and susceptible genotypes separately

in each tray and were allowed to feed upto ten days. Just before conducting the bio-

assay test, larval weights were taken.

3.6.2 Topical Bioassay With Chlorpyriphos

Chlorpyriphos was selected for topical bio-assay test based on survey

conducted in Southern zone of Andhra Pradesh. A serial dilution of chlorpyriphos

with 5 concentrations (10, 5, 2.5, 1.25 and 0.625 ml/lit of water) were prepared and

used in dose-concentration bioassay. Bioassay was conducted by topical application

of 2.0 µl of each concentration of chlorpyriphos. Each concentration was applied

with microapplicator to the mid dorsum of early third instar larvae. For topical

application, ten larvae were taken for each concentration. After topical application,

the larvae were placed in rearing boxes containing blackgram and greengram

flowers, and pods for feeding. A group of ten larvae were kept as control with no

insecticide treatment. The number of dead larvae were recorded after 24, 48, 72

hours.

This data was used to determine LC50 values for M.vitrata against insecticide

on various blackgram and greengram genotypes having various levels of plant

resistance to M.vitrata.

From the LC50 values, LD50 values were calculated by the following equation

(Gast 1961; Heinrichs et al., 1981, 1984):

LD50 = Volume of insecticide applied (µL)

Mean larval weight (µg)× LC50

Chapter IV

RESULTS AND DISCUSSION

A survey was carried out in three different districts of Southern zone of Andhra

Pradesh to record per cent Maruca damage on blackgram and greengram; genotypes of

blackgram and greengram popularly grown and type of insecticides sprayed for

managing it. Further, studies were done on screening of different genotypes of

blackgram and greengram for susceptibility against spotted pod borer, Maruca vitrata

infestation; mechanisms of resistance involved in blackgram and greengram for spotted

pod borer and the effect of plant resistance in popular genotypes of blackgram and

greengram to spotted pod borer, M.vitrata and its role in insecticide tolerance, were

carried out during 2014 and 2015 in Department of Entomology, S.V. Agricultural

College and Regional Agricultural Research Station (RARS), Tirupati. The results of

the present investigations are presented here under.

4.1 SURVEY IN DIFFERENT DISTRICTS OF SOUTHERN ZONE OF

ANDHRA PRADESH

Survey on M.vitrata infestation on blackgram and greengram during late kharif

2014 was carried out in Chittoor, Nellore and Kadapa districts (Southern zone) of

Andhra Pradesh. Data was recorded on per cent Maruca damage as mentioned in

chapter 2 (Materials and Methods). Information about the genotypes preferred by the

farmers for cultivation of blackgram and greengram and the usage of different

insecticides against M.vitrata management was collected by following standard

protocols as mentioned in chapter 2.

4.1.1 Percentage Maruca vitrata Infestation in Different Districts of Southern Zone

of Andhra Pradesh

4.1.1.1 Blackgram

Out of the three districts surveyed, more per cent infestation of spotted pod borer was

observed in Kadapa district (41.99 ± 6.84) followed by Nellore (39.77 ± 5.97) and

Chittoor (38.50 ± 5.54) (Table 4.1).

4.1.1.2 Greengram

Nellore district (42.66 ± 6.54) recorded more per cent infestation of spotted pod

borer followed by Kadapa (41.1 ± 6.93) and Chittoor (39.24 ± 5.91) (Table 4.1).

In all the districts of Southern zone of Andhra Pradesh, the per cent infestation

of Maruca vitrata ranged from 12.66 % to 41.99 % (both blackgram and greengram)

(Plate 4.1a and 4.1b).

The results of the investigation were supported by the observations of Singh

(1997) who carried out survey in Madhya Pradesh, to investigate the incidence of

Maruca testulalis in pigeonpea and reported that the larvae causes a damage of 50-60 %

of plants. Rani et al. (2013) conducted survey and reported the flower infestation

ranged from 11.5-29 % where as pod damage ranged from 18-27.5 %.

4.1.2 Genotypes of Blackgram and Greengram Preferred for Cultivation by the

Farmers in Southern Zone of Andhra Pradesh

4.1.2.1 Blackgram

Five genotypes of blackgram were majorly cultivated in the Southern zone of

Andhra Pradesh viz., LBG-752, LBG-648, PU-31, LBG-123 and LBG-792. Out of

these, LBG-752 (62.2 %) variety occupied the majority of the blackgram growing area

followed by LBG-123 (17.8 %), LBG-792 (14.1 %), PU-31 (4.4 %) and LBG-648

(1.5 %) (Table 4.2).

4.1.2.2 Greengram

Six genotypes of greengram were cultivated in Southern zone of Andhra Pradesh

viz., LGG-460, LGG-407, LGG-480, LGG-406, PM-115 and LGG-450 were observed

for growing. Among these, LGG-460 (59.3 %) occupied more area in cultivation

followed by LGG-450 (22.2 %), PM-115 (11.1 %), LGG-406 (3 %), LGG-480 (2.2 %)

and LGG-407 (2.2 %) (Table 4.2).

Most of the observed genotypes are grown traditionally since many years which

were supplied by the SAUs and Dept. of Agriculture, and some of the farmers retain

some of the harvested produce for growing in next coming seasons. Since the most

preferred genotypes are bushy in nature, the natural enemies such as coccinellid beetles

and dragonflies were observed on insect pests. The results of investigation were

supported by the observations of Rani et al .(2013) who observed the coccinellids,

Cheilomenes sexmaculata (Fabricius) along with spiders and ground spiders in the

pulse ecosystem. Borah and Dutta (2001) observed six hymenopterous parasitoids and

five species of predators.

4.1.3 Insecticide usage by the farmers of Southern zone of Andhra Pradesh against

spotted pod borer infestation

4.1.3.1 Blackgram

From the survey data (Table 4.3), it was found that majority of the farmers

preferred chlorpyriphos (51.9%) insecticide followed by the novaluron (20.7%),

acephate (9.6 %), DDVP (8.9%), quinalphos (4.4%) and thiodicarb (4.4%) to control

the spotted pod borer.

4.1.3.2 Greengram

From the survey data (Table 4.3), it was found that majority of the farmers

preferred insecticide chlorpyriphos (54.1%) followed by the DDVP (17.8%), novaluron

(14.8%), acephate (8.1%), thiodicarb (4.4%) and quinalphos (0.7%) for spraying

against Maruca infestation.

As pulse crops are infested with a number of insects belonging to different

groups such as caterpillars, sucking insects etc., farmers generally rely on insecticides

having a broad spectrum of activity which are at affordable price. It has been found

from the present survey that farmers rely on an insecticide such as chlorpyriphos which

has a broad spectrum of activity and which also possess fumigant action, to control

different types of insects such as webbers as spotted pod borer, insects that are internal

feeders such as pod fly and sucking insects such as aphids, jassids, thrips etc.,

4.2 FIELD SCREENING OF DIFFERENT GENOTYPES OF BLACKGRAM

AND GREENGRAM FOR THEIR SUSCEPTIBILITY TO INCIDENCE OF

Maruca vitrata

A screening trial was laid out with nine cultivars of blackgram and ten cultivars

of greengram for their reaction against the spotted pod borer (M.vitrata) in the wetland

farm, S.V. Agricultural College, Tirupati during August, 2014 as mentioned in chapter

2 (Materials and methods) (Plate 4.2). The data on incidence of the spotted pod borer,

M.vitrata that was recorded on flower buds, flowers and pods of different genotypes of

blackgram and greengram are furnished here under (Tables 4.4, 4.5, 4.6, 4.7, 4.8, 4.9,

4.10, 4.11, 4.12).

4.2.1 Field Screening of Different Genotypes of Blackgram for their Reaction to

Incidence of Maruca vitrata

4.2.1.1 Number of webbings/plant

Data on number of webbings per plant was taken on different genotypes of

blackgram at weekly intervals from 57, 64, 71, 78, 85, 92 DAS (Days After Sowing).

At 57 DAS, no significant differences were observed among different genotypes

of blackgram in terms of number of Maruca webbings per plant (Table 4.4).

At 64 DAS, lowest number of Maruca webbings per plant were observed in

LBG-792(1.33 ± 0.49) followed by LBG-645 (1.4 ± 0.63) (not significantly different).

Highest number of webbings per plant were observed in LBG-790 (2.93 ± 0.96)

followed by LBG-123 (2.2 ± 1.01) (significantly different) and for the remaining

(LBG-752, LBG-20, PU-31, LBG-791 and LBG-709) genotypes, number of Maruca

webbings per plant were on par with each other.

At 71 DAS, lowest webbings were observed in genotype LBG-645 (1.73 ±

0.96). Highest number of webbings per plant were observed in LBG-790 (3.73 ± 1.34)

followed by LBG-123(2.73 ±1.03), PU-31(2.6 ± 1.06) (significantly different) and the

remaining (LBG-709, LBG-20, LBG-792, LBG-791 and LBG-752) genotypes were on

par with each other.

At 78 DAS, lowest number of webbings per plant were observed in genotype

LBG-645 (1.73 ± 0.80). Highest number of webbings per plant were observed in LBG-

790(5.07 ±1.62) which was significant from the remaining (LBG-709, PU-31, LBG-

791, LBG-792, LBG-20, LBG-123 and LBG-752) genotypes, where the number of

webbings per plant were on par with each other.

At 85 DAS, lowest number of webbings per plant were observed in LBG-645

(2.60 ± 0.99). Highest number of webbings per plant were observed in LBG-790 (6.80 ±

1.37), which was significantly different from the remaining (LBG-709, PU-31,

LBG-20, LBG-792, LBG-791, LBG-123 and LBG-752) genotypes, where the number

of webbings per plant were on par with each other.

At 92 DAS, lowest number of webbings per plant were found in LBG-645

(3.33 ± 0.98). Highest number of webbings per plant were observed in LBG-790

(7.67 ± 1.95) which was significantly different from the remaining (LBG-709,

LBG-791, PU-31, LBG-20, LBG-792, LBG-123 and LBG-752) genotypes, where the

number of webbings per plant were on par with each other.

From the mean data, it was observed that lowest number of webbings per plant

were observed in LBG-645(2.02 ± 0.50). Highest number of webbings per plant were

found in LBG-790 (4.60 ± 1.00) and the remaining (LBG-709, LBG-792, LBG-791,

LBG-20, PU-31, LBG-752 and LBG-123) genotypes were on par with each other in the

number of Maruca webbings.

4.2.1.2 Number of Maruca caterpillars/plant

At 57 DAS and 64 DAS, no significant differences were observed among

different genotypes of blackgram in terms of number of caterpillars per plant (Table

4.5).

At 71 DAS, lowest number of caterpillars per plant were found in LBG-709

(1.87 ± 1.30) followed by LBG- 792 (2.4 ± 1.30), LBG-645 (2.27 ± 1.10) (no significant

difference). Highest number of caterpillars per plant were found in LBG-790

(3.73 ± 1.71) followed by LBG-123 (3.6 ± 1.55), LBG-791 (3.2 ± 1.27), PU-31 (3.2 ±

1.15), LBG-752 (3.07 ± 1.03), LBG-20 (2.87 ± 1.51) (no significant difference).

At 78 DAS, lowest number of caterpillars per plant were found in LBG-645

(2.27 ± 1.49). Highest number of caterpillars per plant were found in LBG-790 (6.8 ±

1.61) and the remaining (PU-31, LBG-791, LBG-20, LBG-709, LBG-792, LBG-123

and LBG-752) genotypes were on par with each other.

At 85 DAS, lowest number of caterpillars per plant were found in LBG-645

(2.07 ± 1.44). Highest number of caterpillars per plant were observed in LBG-790

(7.00 ± 1.20) followed by LBG-752(5.87 ± 1.46) (no significant difference) and the

remaining (LBG-709, LBG-123, PU-31, LBG-20, LBG-791 and LBG-792) genotypes

were on par with each other.

At 92 DAS, lowest number of caterpillars per plant were found in LBG-645

(1.6 ± 0.99). Highest number of caterpillars per plant were found in LBG-790

(4.73 ± 1.71) and the remaining (LBG-123, LBG-791, LBG-752, PU-31, LBG-792,

LBG-709 and LBG-20) genotypes were on par with each other.

From the mean data, lowest number of caterpillars per plant were found in LBG-

645 (1.62 ± 0.59) followed by LBG-709 (2.48 ± 0.66) (significantly different). Highest

number of caterpillars per plant were found in LBG-790 (4.07 ± 0.74) followed by

LBG-752 (3.13 ± 0.70) (significantly different), and the remaining (LBG-792,

LBG-791, LBG-123, LBG-20 and PU-31) genotypes were on par with each other

(Table 4.5).

4.2.1.3 Percentage infestation

Percentage infestation was calculated by the formula

Per cent Infestation = 100 plants ofnumber Total

larvae Maruca with infected plants ofNumber

At 57, 64 DAS and 71 DAS, not much significant differences were observed in

Maruca infestation among different blackgram genotypes (Table 4.6).

At 78 DAS, lowest percentage infestation was found in LBG-645 (32.78 ± 2.54)

followed by LBG-792 (32.86 ± 3.71), LBG-791 (33.51 ± 3.8) (not significantly

different). Highest percentage infestation was found in LBG-790 (44.28 ± 5.15) and the

remaining (PU-31, LBG-20, LBG-123, LBG-752 and LBG-709) genotypes were on par

with each other.

At 85 DAS, lowest percentage infestation was observed in LBG-645 (34.44 ±

0.96). Highest percentage infestation was found in LBG-790 (54.50 ± 5.85) followed by

LBG-752 (46.03 ± 6.87), LBG-709 (45.88 ± 8.43), (not significantly different) and the

remaining (LBG-791, LBG-792, PU-31, LBG-20 and LBG-123) genotypes were on par

with each other.

At 92 DAS, lowest percentage infestation was observed in LBG-645 (37.70 ±

2.52). Highest percentage infestation was found in LBG-790 (64.71 ± 6.57) followed by

LBG-709 (54.67 ± 10.46) (not significantly different) and the remaining (LBG-791,

PU-31, LBG-20, LBG-792, LBG-752 and LBG-123) genotypes were on par with each

other.

From the mean data, percentage infestation was found lowest in LBG-645

(33.33 ± 0.83) followed by LBG-791(33.73 ± 3.42) (not significantly different). Highest

percentage infestation was found in LBG-790 (44.60 ± 5.50) followed by LBG-709

(41.11 ± 6.08), LBG-752 (39.09 ± 2.93) and LBG-123 (38.41 ± 3.27) (not significantly

different) and the remaining (LBG-20, LBG-792 and PU-31) genotypes were on par

with each other (Table 4.6).

Number of webbings of M. vitrata in the present investigation varied from

1.20/plant to 7.67/plant between 57DAS to 92DAS. These results were in close

resemblance wIth that of Mohapatra and Srivastava (2002) reported highest number of

webs and larvae of spotted pod borer in pigeonpea genotypes, ICPL 98016 as1.38 webs

and 2.09 larvae per plant at 15 days after flowering (DAF), and 1.48 webs and 1.92

larvae per plant at 30 DAF and lowest number of webs and larvae in ICPL 98013 (1.11

webs and 1.54 larvae per plant at 15 DAF, and 1.18 webs and 1.47 larvae per plant at

30 DAF).

Number of M. vitrata larvae in the present investigation varied from 0.73/plant

to 7.00 larvae/plant, between 57 DAS to 92 DAS. The results of the present

investigation is in close accordance with Jaydeep Halder and Srinivasan (2012), who

reported that the highest number of Maruca larval population was noticed on cowpea

(20.4/plant), followed by urd bean (8.0/plant) and mung bean (7.1/plant), while field

bean (4.3/plant) and pigeon pea (2.6/plant) were on par with each other.

The per cent infestation in the present investigations varied from 29.12 to 49.41

% from57 DAS to 92 DAS in blackgram. These results were supported by the findings

of the Sontakke and Muduli (1990) who reported that the Maruca vitrata per cent

infestation ranged from 8.9 to 22.6 percentage in blackgram for the different genotypes

and Saxena et al. (2002), who reported, highest incidence on flower and flower buds

by Maruca in cowpea (46.1%), followed by field bean (15.4%) and urd bean (11.0%).

The non determinate genotypes (41-50%) showed resistance against spotted pod borer

infestation than the determinate genotypes (66-75%).

The results of the investigation were in accordance with the findings of Krishna

et al. (2006) who have evaluated 25 blackgram genotypes for resistance to M. vitrata

and based on pod damage, the genotypes were classified as resistant (0-12% damage;

LBG 745, LBG 747, LBG 744, LBG 726 and LBG 762), moderately resistant (>15%

damage; LBG 764, LBG 761, LBG 738, LBG 730, LBG 755, LBG 749, LBG 746,

LBG 765 and LBG 727), moderately susceptible (more than 25% damage) or

susceptible (more than 35% damage).

Based on observations number of webbings; number of caterpillar; per cent

infestation, different genotypes of blackgram were arranged into following plant

resistant groups

Characters Resistant Moderately

resistant Susceptible

Number of

webbings

LBG-645

LBG-709

LBG-792

LBG-791

LBG-20

PU-31

LBG-752

LBG-123

LBG-790

Number of

caterpillars

LBG-645

LBG-709

LBG-791

LBG-792

LBG-123

LBG-20

PU-31

LBG-752

LBG-790

Per cent

infestation

LBG-645

LBG-791

LBG-20

LBG-792

PU-31

LBG-123

LBG-752

LBG-709

LBG-790

The genotypes LBG-645, LBG-791 and LBG-790 were classified as resistant,

moderate resistant and susceptible genotypes based on number of webbings per plant

and number of caterpillars per plant and per cent infestation. These genotypes were

further experimented in the laboratory in no choice and free choice experiments, to

confirm the resistant rankings, which were observed in the field condition.

4.2.2 Field Screening of Different Genotypes of Greengram for their Reaction to

Incidence of Maruca vitrata

4.2.2.1. Number of Maruca webbings/plant (1st sowing)

The observations were recorded at 71DAS as all the genotypes have attained

50% flowering at this age of the genotypes.

At 71 DAS, number of webbings per plant were found lowest in WGG-42(1.07 ±

0.25). Highest number of webbings per plant were found in MGG-360(2.73 ± 0.88)

followed by TM-962 (1.67 ± 0.81) (significantly different) and the remaining (PM-110,

LGG-410, LGG-450, LGG-407, LGG-460 PM-115 and PM-112) genotypes were on

par with each other (Table 4.7).

At 78 DAS, lowest number of webbings per plant were observed in WGG-

42(2.53 ± 0.83) followed by LGG-450(3.47 ± 1.06) (not significantly different). Highest

number of webbings per plant were observed in in MGG-360(5.87 ± 1.18) followed by

LGG-410(5.67 ± 1.87) (not significantly different) and the remaining (PM-115, LGG-

460, LGG-407, TM-962, PM-110 and PM-112) genotypes were on par with each other.

At 85 DAS, lowest number of webbings per plant (significantly different) were

observed in WGG-42(2.60 ± 0.73) followed by PM-115(3.93 ± 1.03) (significantly

different), LGG-450(4.00 ± 1.06) (significantly different). Highest number of webbings

per plant were found in MGG-360(6.93 ± 1.10) followed by LGG-410(5.07 ± 1.22)

(significantly different) and the remaining (TM-962, LGG-407, LGG-460, TM-962 and

PM-112) genotypes were on par with each other.

At 92 DAS, lowest number of webbings per plant were found in WGG-42(2.93 ±

0.88) followed by PM-115 (4.47 ± 1.40) (significantly different). Highest number of

webbings per plant were found in MGG-360(7.80 ± 1.14) followed by LGG-410(6.20 ±

1.42) (significantly different) and the remaining (LGG-450, LGG-460, LGG-407, PM-

110 and TM-962) genotypes were on par with each other.

From the mean data, lowest number of webbings per plant were observed in

WGG-42(2.28 ± 0.50). Highest number of webbings per plant were found in MGG-

360(5.83 ± 0.54) followed by LGG-410(4.56 ± 1.04) (significantly different) and the

remaining (LGG-450, PM-115, LGG-460, LGG-407, PM-110, TM-962 and PM-112)

genotypes were on par with each other (Table 4.7).

4.2.2.2 Number of Maruca caterpillars/plant

At 71 DAS, total number of caterpillars per plant were found lowest in PM-110

(0.87 ± 0.74) followed by LGG-410 (0.87 ± 0.64) (not significantly different). Highest

number of caterpillars per plant were observed in MGG-360(3.20 ± 0.86) and the

remaining (WGG-42, LGG-450, LGG-407, PM-112, PM-115, LGG-460 and TM-962)

genotypes were on par with each other.

At 78 DAS, lowest number of caterpillars per plant were observed in WGG-

42(1.07 ± 0.88) followed by TM-962(1.73 ± 1.16), LGG-450(2.00 ± 0.92) (not

significantly different), LGG-407(2.13 ± 0.99) (significantly different with WGG-42).

Highest number of caterpillars per plant were found in MGG-360 (6.53 ± 2.47)

followed by LGG-410(3.33 ± 1.71) (significantly different) and the remaining (PM-115,

LGG-460, PM-110 and PM-112) genotypes were on par with each other. (Table 4.8)

At 85 DAS, lowest number of caterpillars per plant were observed in

WGG-42(3.67 ± 1.11), highest number of caterpillars per plant were found in

MGG-360(7.87 ± 1.12) and the remaining (PM-112, PM-115, LGG-450, LGG-460,

TM-962, PM-110, LGG-407 and LGG-410) genotypes were on par with each other.

At 92 DAS, lowest number of caterpillars per plant were observed in

WGG-42(1.20 ± 0.94). Highest number of caterpillars per plant were found in

MGG-360(6.73 ± 2.52) and the remaining (LGG-407, LGG-460, LGG-450, LGG-410,

PM-110, TM-962, PM-115 and PM-112) genotypes were on par with each other.

From the mean data, lowest number of caterpillars per plant were found in

WGG-42(1.73 ± 0.52). Highest number of caterpillars per plant were observed in

MGG-360(6.08 ± 0.87) and the remaining (LGG-50, LGG-407, LGG-460, TM-962,

PM-110, PM-115, PM-112 and LGG-410) genotypes were on par with each other

(Table 4.8).

4.2.2.3 Percentage infestation

At 71 DAS, there is no significant difference between all the genotypes in per

cent infestation by the Maruca caterpillars.

At 78 DAS, percentage infestation was found lowest in LGG-410(36.91 ± 7.22)

followed by WGG-42(37.58 ± 1.26), LGG-460(38.73 ± 4.88) (not significantly

different). Highest percentage infestation was found in MGG-360(57.07 ± 2.04)

followed by PM-112(53.36 ± 2.95), LGG-407(46.39 ± 11.09), LGG-450(45.68 ± 10.77)

(no significant difference) and the remaining (PM-110, TM-962 and PM-115)

genotypes were on par with each other (Table 4.9).

At 85 DAS, lowest percentage infestation was observed in LGG-410(35.46 ±

5.47) followed by WGG-42(37.58 ± 1.26) (not significantly different). Highest

percentage infestation was found in MGG-360(63.43 ± 3.33) followed by PM-

112(53.36 ± 2.95) (not significantly different) and the remaining (LGG-460, PM-110,

LGG-407, PM-115, TM-962 and LGG-450) genotypes were on par with each other.

At 92 DAS, lowest percentage infestation was observed in WGG-42(37.58 ±

1.26) followed by LGG-410(38.51 ± 8.08), LGG-460(41.45 ± 3.47) LGG-407 (44.80 ±

12.14) (not significantly different). Highest percentage infestation was found in

MGG-360(65.10 ± 1.51) followed by PM-112(56.73 ± 3.79), PM-115(50.79 ± 5.18) (not

significantly different) and the remaining (PM-110, TM-962 and LGG-450) genotypes

were on par with each other.

From the mean data, lowest percentage infestation was observed in LGG-

410(34.04 ± 6.05) followed by WGG-42(36.36 ± 1.96) (not significantly different).

Highest percentage infestation was found in MGG-360(52.78 ± 0.69) followed by PM-

112(47.34 ± 2.36) (not significantly different) and the remaining (LGG-460, PM-110,

LGG-407, TM-962, LGG-450 and PM-115) genotypes were on par with each other

(Table 4.9).

4.2.2.4 Number of Maruca webbings/plant (2nd sowing)

At 57 DAS, number of webbings per plant were found lowest in WGG-42 (1.07

± 0.25). Highest number of webbings per plant were observed in MGG-360(2.27 ±

0.88) and the remaining (TM-962, PM-112, PM-110, LGG-460, LGG-410, LGG-450,

PM-115 and LGG-407) genotypes were on par with each other.

At 64 DAS, lowest number of webbings per plant were found in WGG-42(1.93 ±

0.79) followed by LGG-450(2.07 ± 1.03) (not significantly different). Highest number

of webbings per plant were found in MGG-360(3.20 ± 1.52) followed by PM-112(2.93

± 1.16) (not significantly different) and the remaining (LGG- 407, PM-110, TM-962,

LGG-410 and PM-115) genotypes were on par with each other (Table 4.10).

At 71 DAS, lowest number of webbings per plant were found in WGG-42(2.67 ±

0.97) followed by PM-112(3.27 ± 1.48), LGG-450(3.27 ± 1.10), LGG-460(3.27 ± 1.03),

TM-962(3.40 ± 0.98) (not significantly different). Highest number of webbings per

plant were found in MGG-360(5.20 ± 1.20) and the remaining (PM-110, LGG-410,

LGG-407 and PM-115) genotypes were on par with each other.

At 78 DAS, lowest number of webbings per plant were found in WGG-42(2.80 ±

0.94) followed by PM-112(3.07 ± 0.79), LGG-450(3.60 ± 1.18) (not significantly

different). Highest number of webbings per plant were observed in MGG-360(6.20 ±

0.86) and the remaining (LGG-460, LGG-410, TM-962, PM-110, PM-115 and LGG-

407) genotypes were on par with each other.

At 85 DAS, lowest number of webbings per plant were observed in

WGG-42(2.93 ± 1.22). Highest number of webbings per plant were observed in

MGG-360(7.47 ± 0.91) which was significant from the remaining (PM-112, PM-110,

LGG-450, LGG-410, PM-115, TM-962, LGG-460 and LGG-407) genotypes which

were on par with each other (Table 4.10).

At 92 DAS, lowest number of webbings per plant were found in WGG-42

(2.87 ± 0.91). Highest number of webbings per plant were found in MGG-360

(7.80 ± 1.01) and the remaining (PM-112, PM-115, PM-110, LGG-460, LGG-410,

TM-962, LGG-450 and LGG-407) genotypes were on par with each other.

From the mean data, lowest number of webbings per plant were observed in

WGG-42(2.38 ± 0.63). In MGG-360(5.33 ± 0.67) highest number of webbings per

plant were observed and the remaining (PM-112, LGG-450, PM-110, LGG-460, TM-

962, LGG-410 PM-115 and LGG-407) genotypes were on par with each other.

4.2.2.5 Number of Maruca caterpillars/plant (2nd sowing)

At 57 DAS, lowest number of caterpillars per plant were found in PM-110 (0.53

± 0.51). Highest number of caterpillars per plant were found in MGG-360 (1.80 ± 0.67)

followed by LGG-450(1.13 ± 0.64), LGG-410(1.07 ± 0.70) (significantly different) and

the remaining (TM-962, WGG-42, PM-112, LGG-460, PM-115 and LGG-407)

genotypes were on par with each other (Table 4.11).

At 64 DAS, lowest number of caterpillars per plant were observed in WGG-42

(0.93 ± 0.88). Highest number of caterpillars per plant were found in PM-112 (2.80 ±

1.37) and the remaining (LGG-450, LGG-460, LGG-407, PM-110, MGG-360,

LGG-410, TM-962 and PM-115) genotypes were on par with each other.

At 71 DAS, lowest number of caterpillars per plant were found in WGG-42

(3.27 ± 1.16). Highest number of caterpillars per plant were found in MGG-360

(6.40 ± 2.06) followed by PM-115(4.80 ± 1.20), LGG-410 (4.73 ± 1.66), LGG-407

(4.67 ± 1.58) (significantly different) and the remaining (LGG-460, TM-962, LGG-450,

PM-112 and PM-110) genotypes were on par with each other.

At 78 DAS, lowest number of caterpillars per plant were found in WGG-42

(2.07 ± 1.48) followed by LGG-450 (2.47 ± 1.12) (not significantly different). Highest

number of caterpillars per plant were observed in MGG-360 (6.60 ± 2.02) and the

remaining (LGG-407, PM-112, LGG-410,TM-962,PM-110,LGG-460 and PM-115)

genotypes were on par with each other.

At 85 DAS, lowest number of caterpillars per plant were found in WGG-42

(2.27 ± 1.62) followed by PM-112(4.20 ± 1.74) (significantly different). Highest

number of caterpillars per plant were observed in MGG-360 (8.20 ± 2.67) followed by

LGG-407(6.20 ± 1.89) (significantly different) and the remaining (LGG-460, PM-110,

LGG-410, PM-115, TM-962 and LGG-450) genotypes were on par with each other.

At 92 DAS, lowest number of caterpillars per plant were found in WGG-42

(1.87 ± 0.83). Highest number of caterpillars per plant were observed in MGG-360

(4.93 ± 1.28) followed by PM-110 (3.07 ± 1.33), PM-112 (3.07 ± 1.16), TM-962

(3.07 ± 1.33) (significantly different) and the remaining (LGG-450, PM-115, LGG-407,

LGG-410 and LGG-460) genotypes were on par with each other.

From the mean data, lowest number of caterpillars per plant were found in

WGG-42(1.84 ± 0.54). Highest number of caterpillars per plant were found in

MGG-360(5.02 ± 0.84) and the remaining (LGG-450, PM-112, LGG-460, PM-110,

TM-962, LGG-410, LGG-407 and PM-115) genotypes were on par with each other

(Table 4.11).

4.2.2.6 Percentage infestation (2nd sowing)

At 57 DAS, lowest percentage infestation was observed in MGG-360(24.64 ±

1.44). Highest percentage infestation was observed in PM-110(31.53 ± 1.68) followed

by LGG-450(29.33 ± 3.68) ,LGG-410(29.05 ± 4.83), WGG-42(28.94 ± 2.00), PM-

115(28.30 ± 1.85), PM-112(27.84 ± 1.54), TM-962(27.54 ± 2.12) (not significantly

different) and the remaining (LGG-407, LGG-460) genotypes were on par with each

other (Table 4.12).

At 64 DAS, lowest percentage infestation was found in TM-962(27.63 ± 3.48).

Highest percentage infestation was found in WGG-42(42.36 ± 3.02) followed by MGG-

360(41.19 ± 5.35) (not significantly different) and the remaining (LGG-450, PM-112,

PM-115, LGG-407, PM-110, LGG-460 and LGG-410) genotypes were on par with

each other.

At 71 DAS, lowest percentage infestation was observed in TM-962 (32.81 ±

3.58) followed by LGG-450(34.36 ± 7.17), PM-112 (35.25 ± 3.65) (not significantly

different). Highest percentage infestation was found in MGG-360(45.95 ± 2.68)

followed by WGG-42(42.36 ± 3.02) (not significantly different) and the remaining

(PM-115, LGG-407, PM-110, LGG-460 and LGG-410) genotypes were on par with

each other.

At 78 DAS, lowest percentage infestation was observed in PM-112(35.25 ±

3.65) followed by TM-962(36.32 ± 6.07), LGG-450 (37.80 ± 10.17) (not significantly

different). Highest percentage infestation was observed in MGG-360(47.54 ± 4.76) and

the remaining (PM-110, LGG-460, PM-115, LGG-407, WGG-42 and LGG-410)

genotypes were on par with each other.

At 85 DAS, lowest percentage infestation was found in LGG-460(41.48± 2.56)

followed by WGG-42(42.36 ± 3.02), LGG-450(42.55 ± 7.61), PM-112(42.78 ± 5.30),

LGG-407(43.40 ± 6.05), PM-115(44.91 ± 2.75), TM-962(44.91 ± 4.25), PM-110

(46.48 ± 3.06), LGG-410(47.62 ± 4.12) (not significantly different). Highest percentage

infestation was found in MGG-360(57.39 ± 4.78).

At 92 DAS, lowest percentage infestation was observed in WGG-42 (44.21 ±

0.40) followed by PM-110 (46.48 ± 3.06), PM-112 (46.50 ± 5.70), PM-115 (48.24 ±

6.47), LGG-407 (48.50 ± 5.05), LGG-460(48.52 ± 6.09), LGG-450 (50.74 ± 9.22),

LGG-410(51.06 ± 4.07), TM-962(51.84 ± 6.48). Highest percentage infestation was

found in MGG-360(64.08 ± 6.06).

From the mean data, lowest percentage infestation was found in PM-112(36.51

± 2.75), TM-962(36.84 ± 3.16), LGG-450(37.61 ± 6.63), PM-115(38.52 ± 2.65), LGG-

407(38.97 ± 3.57) (not significantly different). Highest percentage infestation was

observed in MGG-360(46.79 ± 3.43) and the remaining (LGG-460, PM-110, WGG-42,

LGG-410) genotypes were on par with each other (Table 4.12).

The number of webbings per plant, number of caterpillars per plant, per cent

infestation in different genotypes of blackgram and greengram in the present

investigation varied from 1.40 to 5.19, 0.89 to 3.12 and 19.27 to 50.02 from 57 DAS to

92 DAS (both in first and second planting).

These results were supported by the findings of the Sontakke and Muduli (1990)

who reported that the per cent infestation of Maruca ranged from 6.5 to 38.0% in

greengram. Jaydeep Halder and Srinivasan (2012) noticed 7.1 larval population of

Maruca on mung bean per plant. Mohapatra and Srivastava (2002) reported highest

number of webs and larvae of Maruca vitrata in ICPL 98016 (1.38 webs and 2.09

larvae per plant at 15 days after flowering (DAF), and 1.48 webs and 1.92 larvae per

plant at 30 DAF) and lowest webs and larvae in ICPL 98013 (1.11 webs and 1.54 larvae

per plant at 15 DAF, and 1.18 webs and 1.47 larvae per plant at 30 DAF). Saxena et al.

(2002) observed that the non determinate genotypes (41-50%) showed resistance

against spotted pod borer infestation than the determinate genotypes (66-75%).

Mandal (2005) screened and observed that the genotypes ML 5, ML 408 and

RMG 266 were resistant (less than 5% pod damage), the genotypes ML 131, ML 505,

RMG 275, Pusa 8971 and Pusa 8972 were moderately resistant (5.1-10% pod damage);

PDM 219, RMG 175, RMG 202, Pusa 8974, Pusa Baisakhi and K851 were moderately

susceptible (10.1-15% pod damage); PDM 216, ML 537, PDM 86-199 and WBM 202

were susceptible (>15% pod damage) to spotted pod borer.

Based on observations on number of webbings; number of caterpillar; per cent

infestation, different genotypes of greengram were arranged into following plant

resistant groups

1st planting 2nd planting

Characters Resistant Moderate

resistant Susceptible Resistant

Moderate

Resistant Susceptible

Number of

webbings

WGG-42

LGG-450

PM-115

LGG-460

LGG-407

PM-110

TM-962

PM-112

LGG-410

MGG-360

WGG-42

PM-112

LGG-450

PM-110

LGG-460

TM-962

LGG-410

PM-115

LGG-407

MGG-360

Number of

caterpillars

WGG-42

LGG-450

LGG-407

LGG-460

TM-962

PM-110

PM-115

PM-112

LGG-410

MGG-360

WGG-42

LGG-450

PM-112

LGG-460

PM-110

TM-962

LGG-410

LGG-407

PM-115

MGG-360

Per cent

infestation

LGG-410

WGG-42

LGG-460

PM-110

LGG-407

TM-962

LGG-450

PM-115

PM-112

MGG-360

PM-112

TM-962

LGG-450

PM-115

LGG-407

LGG-460

PM-110

WGG-42

LGG-410

MGG-360

From the different categories of greengram genotypes given in the above table,

the genotypes WGG-42, TM-962 and MGG-360 that were consistent in their rankings

were classified as resistant, moderate resistant and susceptible genotypes based on

number of webbings per plant and number of caterpillars per plant. These genotypes

were taken for further investigation in the laboratory for confirmation of resistance that

has been observed in the field condition.

The results were supported by the observations of Rani et al. (2008) who have

screened and reported that the varieties, MGG 366 358, MGG 359, MGG 360, MGG

364 and MGG 367 were tolerant to the spotted pod borer damage in both kharif and

rabi seasons compared to the moderately susceptible check, MGG 295.

Greengram variety MGG 360, was reported as tolerant vareity to spotted pod

borer damage by Rani et al. (2008). However, in the present investigations, MGG 360

showed a susceptible reaction in terms of number of webbings and number of Maruca

larvae per plant. The differences in resistance reaction observed in MGG 360 could be

due to the local environmental conditions prevailing during the period of

experimentation.

Environmental conditions plays a vital role in the expression of resistance in

crop varieties to insect pest. Breakdown of resistance in sorghum germplasm to midge

fly, Stenodiplosis sorghicola was reported by Sharma et al. (1999). According to them

sorghum germplam DJ 6514 and ICSV 197, which are highly resistant to sorghum

midge in India, showed a susceptible reaction at Alupe, Kenya. These authors have

reported that the variation in the reaction of sorghum genotypes across locations may be

partly due to the influence of environment, which might have affected the glume and

grain characteristics and thus a change in their resistance reaction to sorghum midge

fly.

4.3 STUDIES ON THE MECHANISMS OF RESISTANCE OPERATING IN

THE SELECTED GENOTYPES OF BLACKGRAM AND GREENGRAM

Blackgram and greengram varieties that were designated as resistant, moderate

resistant and susceptible from the field screening, were further experimented in the

laboratory, in free choice and no choice techniques (Plate 4.3) to confirm the resistance

rankings that observed in the field.

4.3.1 Biology of M.vitrata in Resistant, Moderate resistant and Susceptible

Genotypes of Blackgram

From the field screening of different genotypes of blackgram, following entries

were selected as R, MR and S and were used in laboratory experiments to study the

mechanism of resistance involved in these genotypes to Maruca vitrata.

LBG-645 – Resistant; LBG-791- Moderate resistant and LBG-790 - Susceptible

4.3.1.1 Larval Free-Choice Studies of M. Vitrata

Larval free choice arena test to assess the larval preference of Maruca vitrata for

selected genotypes of blackgram was performed as reported by Jackai (1991). Tender

pods of test genotypes were arranged radially along the periphery of a Petri plate of 9''

diameter lined with moist blotting paper. Number of Maruca larvae visiting the test

genotypes were counted after 24 hrs and expressed as larval preference.

In larval free choice experiment, it was observed that more number of larvae of

Maruca preferred the genotype LBG-790 (2.57 ± 0.98) (susceptible) which were

significantly different from LBG-645 (resistant) which were preferred by few number

of Maruca larvae (1.57 ± 0.54). Larval preference of genotype LBG-791 (1.86 ± 0.69)

(moderate resistant) were in between LBG-790 and LBG-645. The results are presented

in Table 4.13.

4.3.1.2 Biology of Maruca vitrata on Selected Genotypes of Blackgram

As the observations on biology of Maruca on blackgram and greengram are

limited, the results of present investigations are discussed and correlated with biology

of Maruca on other pulse crops.

4.3.1.2.1 Second instar and third instar larval duration

The durations of 2nd and 3rd instar larvae were not significantly different when

reared on selected genotypes of blackgram (Table 4.14).

4.3.1.2.3 Fourth instar larval duration

The fourth instar larvae were creamy white in colour with reddish eyes and

mandibles (personal observations). The duration of the fourth instar larva was less on

LBG-790 (2.43 ± 0.54 days) (susceptible) followed by 2.57 ± 0.54 days on LBG-791

(on par with) (moderate resistant) . Highest larval duration (3.00 ± 0.54 days) of fourth

instar was observed when larvae were reared on LBG-645 (resistant).

4.3.1.2.4 Fifth instar larval duration

The larva was deep creamy white in colour with dark brown head, prothoracic

shield and sclerites (personal observations). The duration of the fifth instar larva was

least 2.86 ± 0.54 days when larvae were reared on LBG-790 (susceptible) followed by

3.00 ± 0.54 days on LBG-645 (resistant) (not significantly different) and 3.57 ± 0.54

days on LBG-791 (moderate resistant) (significantly different).

4.3.1.2.5 Total larval duration

The total duration of the larvae was least (11.86 ± 0.54 days) on LBG-790

(susceptible) followed by 12.71 ± 0.54 days in LBG-791 (moderate resistant) and

13.00 ± 0.54 days in LBG-645 (resistant) (on par with each other).

4.3.1.2.6 Third instar larval weight

The lowest larval weight of the third instar (0.0325 ± 0.019 gms) was observed,

when larvae were reared on LBG-645 (resistant) (significantly different) followed by

0.0362 ± 0.0022 gms on LBG-791 (moderate resistant) (significantly different). Highest

larval weights (0.0418 ± 0.0058 gms), when larvae were reared on LBG-790

(susceptible) variety (significantly different).

4.3.1.2.7 Fourth instar larval weight

The lowest larval weight of the fourth instar (0.0449 ± 0.0021 gms) was

observed when larvae were reared on LBG-645 (resistant) followed by (0.0483 ±

0.0013 gms) on LBG-791 (moderate resistant) (not significantly different). Highest

larval weights of fourth instar was observed as 0.0556 ± 0.0053 gms, when larvae were

reared on LBG-790 (susceptible) (significantly different).

4.3.1.2.8 Pupal weight

The pupae was green in colour initially and later turns to brown colour. The

pupal weight was lowest (0.0398 ± 0.0021 gms) when they were reared on LBG-645

(resistant) followed by LBG-791 (moderate resistant) (0.0422 ± 0.0021 gms). Highest

pupal weights were observed, when the insects were reared on LBG-790 (susceptible)

(0.0447 ± 0.0033 gms) (all are not significantly different).

4.3.1.2.9 Pupal duration

The duration of the pupae was 4.52 ± 0.5 days on LBG-790 (susceptible)

followed by 5.21 ± 0.47 days on LBG-791 (moderate resistant)(significantly different)

and 5.57 ± 0.54 days in LBG-645 (resistant) (significantly different) genotypes .

4.3.1.2.10 Adult longevity

Adult was a medium sized moth with brown wings and creamy white to brown

body with long legs. Fore wings have small semi transparent bands and the hind wings

were silvery white with a brown spot at the apical margin (personal observations). The

longevity of the adults was 4.98 ± 0.56 days on LBG-790 (susceptible) followed by

5.79 ± 0.64 days on LBG-791 (moderate resistant) (significantly different). Highest

adult longevity was observed 6.45 ± 0.59 days, when insects were reared on LBG-645

(resistant) (significantly different).

4.3.2 Biology of M.vitrata in Resistant, Moderate resistant and Susceptible

Genotypes of Greengram

From the field screening of different genotypes of greengram, following entries

were selected as R, MR and S and were used in laboratory experiments to study the

mechanism of resistance involved in these genotypes to Maruca vitrata.

Resistant – WGG 42; Moderate resistant – TM 962 and Susceptible – MGG 360

4.3.2.1 Larval Free-Choice Studies of M. Vitrata

It was observed that more number of larvae of Maruca preferred the variety

MGG-360 (2.57 ± 0.79) (susceptible) which were significantly different from WGG-42

(resistant) which were preferred by few number of Maruca larvae (1.57 ± 0.53). Larval

preference of variety TM-962 (1.86 ± 0.69) (moderate resistant) were in between

MGG-360 and WGG-42. The observed results were presented in the table 4.15

The present results are in close agreement with the findings of Jaydeep Halder

and Srinivasan (2011) who reported that the highest larval orientation was observed in

GC-9708 (susceptible variety of cowpea) both in pods (18%) and flowers (13%) than

the tolerant variety (HC-270). Jaydeep Halder et al . (2006) also reported that highest

larval orientation was observed in LGG-450 (susceptible) both in pods (17%) and

flowers (14%) than the tolerant variety, LGG-497 of mungbean.

4.3.2.2 Biology of Maruca vitrata on Selected Genotypes of Greengram

As the observations on biology of Maruca on blackgram and greengram are

limited, the results of present investigations are discussed and correlated with biology

of Maruca on other pulse crops.

4.3.2.2.1 Second instar larval duration

The duration of the second instar larva of spotted pod borer is 3.00 ± 0.00 days,

when reared on MGG-360(susceptible) followed by 3.14 ± 0.38 days on WGG-42

(resistant) (not significantly different) and 3.57 ± 0.53 days in TM-962 (moderate

resistant) (significantly different) genotypes (Table 4.16).

The results of the findings were supported by the observations of Sonune et al.

(2010) who reported that the second instar larval duration was 2.80 ± 0.70 days on

blackgram. The second instar larval duration was 1.35 ± 0.10 days on cowpea as

reported by Naveen et al. (2009).

4.3.2.2.2 Third instar larval duration

The duration of third instar larva was 3.29 ± 0.49 days on TM-962 (moderate

resistant) followed by 3.43 ± 0.53 days in MGG-360 (susceptible) and 3.71 ± 0.49 days

in WGG-42 (resistant) (on par with each other).

The results of the findings were supported by the observations of Sonune et al.

(2010) who reported that the third instar larval duration was 2.80 ± 0.66 days on

blackgram. Panickar and Jhala (2007) reported that the duration of the third instar was

2.75 days. 2.42 days of third instar larval duration was observed in pigeonpea by

Ghorpade et al. (2006).

4.3.2.2.3 Fourth instar larval duration

The duration of the fourth instar larva was 2.14 ± 0.38 days on MGG-360

(susceptible) (significantly different) followed by 2.71 ± 0.49 days in TM-962

(moderate resistant) and 2.86 ± 0.38 days on WGG-42 (resistant) (not significantly

different).

The results of the findings were supported by the observations of Sonune et al.

(2010) who reported that the fourth instar larval duration was 2.76 ± 0.72 days on

blackgram. The fourth instar duration was in the range of 2.08 ± 0.16 days in cowpea

by the observations of Naveen et al. (2009).

4.3.2.2.4 Fifth instar larval duration

The duration of the fifth instar larva was 2.57 ± 0.53 days on MGG-360

(susceptible) (significantly different) followed by 3.43 ± 0.53 days on TM-962

(moderate resistant) and 3.71 ± 0.49 days on WGG-42 (resistant) (not significantly

different).

The results of the findings were supported by the observations of Naveen et al.

(2009) who reported that the fifth instar larval duration was 3.50 ± 0.25 days in cowpea.

According to the observations of the Sonune et al. (2010) the fifth instar larval duration

was 3.60 ± 0.64 days in blackgram.

4.3.2.2.5 Total larval duration

The total duration of the larvae was 11.14 ± 1.21 days on MGG-360

(susceptible) (significantly different) followed by 13.00 ± 1.15 days on TM-962

(moderate resistant) and 13.43 ± 0.53 days on WGG-42 (resistant) (significantly

different).

The results of the findings were supported by the observations of Chaitanya

et al. (2012) who reported that the total larval duration was 9.52 ± 0.71 days in

pigeonpea. The mean larval duration was 14.04 ± 0.97 days in blackgram according to

the observations of Sonune et al. (2010). According to Shukla et al. (2008) the average

larval duration was 14.1 days in cowpea. Chandrayudu et al. (2005) reported that the

larval duration was 9.24 to 11.65 days in cowpea.

4.3.2.2.6 Third instar larval weight

The lowest larval weight of the third instar (0.0342 ± 0.0018 gms) was observed,

when larvae were reared on WGG-42 (resistant) (significantly different) followed by

0.0380 ± 0.0035 gms on TM-962 (moderate resitant) (significantly different). Highest

larval weights (0.0440 ± 0.0021gms), were observed, when larvae were reared on

MGG-360 (susceptible).

4.3.2.2.7 Fourth instar larval weight

The lowest larval weight of the third instar (0.0444 ± 0.0026 gms) was observed,

when larvae were reared on WGG-42 (resistant) (not significantly different) followed

by 0.0459 ± 0.0031 gms on TM-962 (moderate reisstant). Highest larval weights

(0.0525 ± 0.0016 gms), were observed, when larvae were reared on MGG-360

(susceptible) (significantly different).

4.3.2.2.8 Pupal weight

Lowest pupal weight (0.0397 ± 0.0020) were observed, when insects were

reared on WGG-42 (resistant) (significantly different) followed by TM-962 (moderate

resistant) (0.0425 ± 0.0019) (significantly different) and (0.0468 ± 0.0012) gms, when

insects were reared on MGG-360 (susceptible) (significantly different).

Oghiakhe et al. (1993) have reported that the mean pupal weight ranged from

43.5 to 54.5 mg on floral buds, 38.5 to 58.6 mg on flowers and 42.7 to 58.6 mg on

sliced pods of cowpea cultivars. The pupal weight was 0.04 ± 0.01 g according to the

observations of Zhao Sheng et al. (2009).

4.3.2.2.9 Pupal duration

The duration of the pupa was 4.52 ± 0.5 days on MGG-360 (susceptible)

(significantly different) followed by 5.21 ± 0.47 days in TM-962 (moderate resistant)

(significantly different) and 5.55 ± 0.55 days on WGG-42 (resistant) genotypes

(significantly different).

The pupal period lasted for about 7.25 ± 0.82 days in pigeonpea according to the

observations of Chaitanya et al. (2012). Sonune et al. (2010) reported that the pupal

duration was 10.84 ± 1.79 days in blackgram. Panickar and Jhala (2007) demonstrated

that the pupal duration was 5.36 days in cowpea.

4.3.2.2.10 Adult longevity

The longevity of the adults was 5.21 ± 0.52 days on MGG-360 (susceptible)

(significantly different) followed by 5.79 ± 0.64 days on TM-962 (moderate resistant)

(significantly different) and 6.45 ± 0.6 days on WGG-42 (resistant) (significantly

different) (Table 4.16).

The results of the findings were strongly supported by the observations of

Chaitanya et al. (2012) who reported that the mean longevity of the adult was

8.83 ± 0.82 days. Zhao Sheng et al. (2009) observed that the female and male longevity

reached 6.00 ± 1.22 and 5.58 ± 0.59 days, respectively.

4.4 PHYSICAL AND BIOCHEMICAL MECHANISMS OF RESISTANCE

AGAINST SPOTTED POD BORER AND THEIR CORRELATION AND

REGRESSION STUDIES WITH INSECT CHARACTERS

Both biophysical and biochemical constituents (viz., protein content, phenol

content, and reducing sugar content) of selected blackgram and greengram genotypes

were studied with respect to performance of Maruca.

4.4.1 Biophysical and Biochemical Constituents of Blackgram Genotypes

4.4.1.1 Trichome density

Number of trichomes present on abaxial leaf surfaces were counted (per 0.25

cm2 leaf area) and are presented in Table 4.17

The lowest trichome density was observed in case of LBG-791 (37.43 ± 4.28)

(moderate resistant) (not significantly different). The highest trichome density was

found in LBG-645 (41.57 ± 4.04) (resistant) followed by LBG-790 (39.71 ± 2.63)

(susceptible) and (not significantly different).

4.4.1.2 Leaf area

The lowest leaf area was reported in LBG-790 (156.29 ± 4.57) (susceptible) (not

significantly different). The highest leaf area was found in LBG-645(159.71 ± 3.55)

(resistant) followed by LBG-791 (159.43 ± 4.50) variety (not significantly different).

4.4.1.3 Leaf dry weight

The lowest leaf dry weight was recorded in LBG-790 (0.72 ± 0.04) (susceptible)

(not significantly different). The highest leaf dry weight was observed in LBG-645

(0.75 ± 0.03) (resistant) followed by LBG-791 (0.74 ± 0.04) (moderate resistant) (not

significantly different).

4.4.1.4 Leaf toughness

Leaf toughness is less in LBG-645 (210.88 ± 4.03) (resistant) (not significantly

different). The highest leaf toughness was recorded in LBG-790 (215.65 ± 5.48)

(susceptible) followed by LBG-791 (214.43 ± 5.53) (moderate resistant) (not

significantly different).

4.4.1.5 Chlorophyll content

The lowest chlorophyll content was found in resistant variety, LBG-645 (36.4 ±

4.87) (significantly different). The highest chlorophyll content was observed in

susceptible variety, LBG-790 (48.75 ± 3.15) followed by moderate resistant variety,

LBG-791 (44.9 ± 2.26) (not significantly different).

4.4.1.6 Plant height

The plant height was observed to be lowest in susceptible variety, LBG-790

(34.88 ± 1.84). The plant height was found to be highest in resistant variety, LBG-645

(35.36 ± 1.64) followed by moderate resistant variety, LBG-791 (35.1 ± 2.03) (not

significantly different).

4.4.2 Biochemical Constituents in Blackgram Genotypes

Biochemical constituents viz., protein content, phenol content, and reducing

sugar content of leaves of different host plants were estimated as per the protocols

mentioned in materials and methods, and are expressed in mg/g of fresh leaves (Table

4.18).

4.4.2.1 Phenol content

Lowest amount of phenols was found in leaves of susceptible variety, LBG-790

(68.55 ± 0.38 mg/g) (significantly different). The resistant variety, LBG-645 leaves

contains more amount of phenols (70.37 ± 0.21 mg/g) (significantly different) followed

by moderate resistant variety, LBG-791 (69.27 ± 0.26 mg/g).

4.4.2.2 Protein content

In resistant variety, LBG-645, lowest amount of protein (148.52 ± 0.46 mg/g)

was observed in the leaves (significantly different). The highest protein content was

observed in the leaves of susceptible variety, LBG-790 (151.92 ± 0.73 mg/g) followed

by moderate resistant variety, LBG-791 (149.97 ± 0.72 mg/g) (significantly different).

4.4.2.3 Reducing sugars

The lowest amount of reducing sugars was recorded in resistant variety, LBG-

645 (25.2 ± 0.35 mg/g) (significantly different). In susceptible variety, LBG-790,

highest amount of reducing sugars (31.71 ± 0.37 mg/g) was found followed by the

moderate resistant variety, LBG-791 (26.31 ± 0.38 mg/g) (significantly different).

4.4.3 Correlation Study of Different Growth Parameters of M.Vitrata on

Blackgram Varietal Characters (Biophysical and Biochemical)

A statistical analysis was done to correlate the performance of spotted pod borer

on different genotypes of blackgram with that of host plant physical and biochemical

constituents.

4.4.3.1 Number of insect larvae in each treatment after 24 hours

The number of larvae in each treatment i.e., larval orientation was negatively

correlated with total phenol content (r= -0.537) of different genotypes of blackgram and

positively correlated with reducing sugars (r=0.486) (both are significant at 0.05 level)

(Table 4.19).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. Number of larvae in each treatment after 24 hours

could be explained by the multiple regression model.

y = 30.360 + 0.000 (trichome density) - 0.010 (chlorophyll) - 0.258 (phenols) -

0.079(proteins) + 0.043(reducing sugars) (R2=0.351) (Table 4.20).

According to the regression equation, influence of trichome density, chlorophyll,

phenols, proteins and reducing sugars on larval orientation is upto 35.1 % (R2=0.351).

No significant correlations were observed between 2nd and 3rd instar larval

durations with that of biophysical and biochemical constituents of different genotypes

of blackgram

4.4.3.2 Fourth instar larval duration

Fourth instar larval duration was negatively correlated with chlorophyll content

(r= - 0.502) and positively correlated with phenols (r=0.522) (both are significant at

0.05 level).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. Fourth instar larval duration could be explained by

the following regression model.

y= -61.509 + 0.489(trichome density) - 0.02 (SCMR) + 0.27 (phenols) + 0.311

(proteins) -0.123 (reducing sugars) (R2=0.347)

According to the regression equation, influence of trichome density, chlorophyll

content, phenols, proteins and reducing sugars content on fourth instar larval duration is

upto 34.7% (R2=0.347).

4.4.3.3 Third instar larval weight

Third instar larval weight was negatively correlated with phenols (r= -0.667)

(significant at 0.01 level). Whereas, a positive correlation was observed with

chlorophyll (r=0.556), proteins (r=0.691) and reducing sugars (r=0.693) (all are

significant at 0.01 level).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. Third instar larval weight could be explained by the

following regression model.

y= 0.004 - 0.002(trichome density) - 0.0000403(chlorophyll) - 0.001(phenols) + 0.001

(proteins) + 0.001(reducing sugars) (R2=0.530)

According to the regression equation, influence of trichome density, chlorophyll

content, phenols, proteins and reducing sugars on fourth instar larval weight is upto

53% (R2=0.530).

4.4.3.4 Fourth instar larval weight

Fourth instar larval weight was negatively correlated with phenols (r= - 0.733 at

0.01 level). Whereas, a positive correlation was found with chlorophyll content(r=0.629

at 0.01 level), proteins (r=0.812 at 0.01) and reducing sugars (r=0.809 at 0.01).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. Fourth instar larval weight could be explained by

the following regression model.

y= -0.15 + 0.001(trichome density) - 0.00000421 (chlorophyll) - 0.001 (phenols) +

0.002 (proteins) + 0.001(reducing sugars) (R2=0.701).

According to the regression equation, influence of trichome density, chlorophyll

content, proteins, phenols and reducing sugars on fourth instar larval weight is upto

70.1 % (R2=0.701).

4.4.3.5 Pupal weight

Pupal weight was positively correlated with chlorophyll content (r=0.545 at

0.05), proteins (r=0.767 at 0.01), reducing sugars (r=0.744 at 0.01). Whereas , a

negative correlation was found with phenols (r= -0.665) (significant at 0.01 level).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. Pupal weight could be explained by the following

regression model.

y= -0.088 + 0.00(trichome density) – 0.000048(chlorophyll) + 0.0001(phenols) + 0.001

(proteins) + 0.0001(reducing sugars) (R2=0.613)

According to the regression equation, influence of trichome density, chlorophyll

content, phenols, proteins and reducing sugars on pupal weight is upto 61.3 %

(R2=0.613).

4.4.3.6 Pupal duration

Pupal duration was positively correlated with phenols (r=0.904) (significant at

0.01 level). Whereas, a negative correlation was observed with chlorophyll content

(r= - 0.721), proteins (r= - 0.892) and reducing sugars (r= - 0.959) (all are significant at

0.01 level).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. Pupal duration could be explained by the following

regression model.

y= -6.1 + 0.005(trichome density) + 0.007(chlorophyll) + 0.231(phenols) -

0.016(proteins) -0.1 (reducing sugars) (R2=0.966)

According to the regression equation, influence of chlorophyll content, phenols,

proteins and reducing sugars is upto 96.6 % (R2=0.966).

4.4.3.7 Adult longevity

Adult longevity was negatively correlated with chlorophyll content (r = -0.811),

proteins (r = - 0.885) and reducing sugars (r= -0.906) (all are significant at 0.01 level).

Whereas, a positive correlation was observed with phenols (r=0.900) (significant at

0.05 level) (Table 4.19).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. Adult longevity could be explained by the

following regression model.

y= 0.721 – 0.019(trichome density) – 0.018(chlorophyll) – 0.245(phenols) – 0.058

(proteins) – 0.086(reducing sugars) (R2=0.886).

According to the regression equation, influence of trichome density, chlorophyll

content, phenols, proteins and reducing sugars on adult longevity is upto 88.6 %

(R2=0.886) (Table 4.20).

Overall influence of biophysical and biochemical constituents on spotted pod borer

performance on blackgram genotypes

Chlorophyll

Weight of 3rd instar, 4th instar larvae and pupal weight were positively correlated

with chlorophyll content (SCMR values) where as the chlorophyll content was

negatively correlated with larval duration of 4th instar larvae, pupal duration and adult

longevity. This could be due to the fact chlorophyll content has increased the

susceptibility of host plant to M. vitrata, where more chlorophyll content has resulted in

more larval weights and less larval, pupal durations and adult longevity.

Phenols

Phenols had significant negative correlations with third instar and fourth instar

larval weights, pupal weights, larval orientation and positive correlation with fourth

instar larval duration, pupal duration and adult longevity. The results which were

obtained were supported by the observations of Anantharaju and Muthiah (2008) who

reported that the LRG-41 variety of pigeonpea shows resistance to spotted pod borer

infestation and gives more yield due to the presence of higher amounts of phenolic

contents. Halder and Srinivasan (2007) observed that the phenols were highest (21.72

mg/g) in the resistant cultivar, LBG-611 than the susceptible cultivar, LBG-17 (20.41

mg/g). Jaydeep Halder et al. (2006) have studied and reported that the phenols were

highest in the resistant cultivar LGG-497 (21.03 mg/g) than the susceptible cultivar

LGG-450 (20.00 mg/g).

Proteins

Proteins showed a significant positive correlation with third instar, fourth instar

larval weights and pupal weights and significant negative correlation with pupal

duration and adult longevity. This may be due to the palatability of the proteins present

in the tested genotypes, the larvae feeds on more proteins and this contributing to

increase in larval and pupal weights.

The above outcome results were supported by the observations of the Sujithra

and Srinivasan (2012) who observed that highly spotted pod borer susceptible variety

AVT-FB(80) 15-6-4 had highest amount of protein (28.9%) as compared to tolerant

variety TCR-137 which had 19 % of proteins . The highly susceptible variety LBG-17

had the highest amount of protein (24.3%) and the lowest values were recorded in the

highly tolerant variety LBG-611 which had 21.6% according to the reports of Halder

and Srinivasan (2007).

Reducing sugars

A significant positive correlation was shown by the reducing sugars with the

larval orientation (number of insect larvae after 24 hours), third instar larval weight,

fourth instar larval weight and pupal weights and the reducing sugars shows the

negative correlation with the pupal duration and adult longevity. These observations

were may be due to association of proteins with reducing sugars, that increases the

palatability of the host plant and increasing the consumption rate of the larvae, leading

to increased larval and pupal weights.

Due to this, the larval orientation was seen more after 24 hours duration. Sujithra

and Srinivasan (2012) observations were shown accordance to the above reported

results who reported that highly susceptible variety AVT-FB(80) 15-6-4 had highest

amount of reducing sugar (1.72 %) as compared to tolerant variety TCR-137 which had

1.05 % of reducing sugars. Halder and Srinivasan (2007) reported that the highly

susceptible variety LBG-17 had the highest amount of reducing sugar (0.62 mg/g), and

the lowest values were recorded in the highly tolerant variety, LBG-611 which had 0.50

mg/g.

4.4.4 Biophysical and Constituents of Greengram Genotypes

4.4.4.1 Trichomes

The lowest trichomes was observed in moderate resistant variety, TM-962

(44.86 ± 6.18) (significantly different). Highest trichomes was found in resistant

variety, WGG-42 (55.29 ± 6.75) followed by susceptible variety, MGG-360

(52.71 ± 5.25) (not significantly different) (Table 4.21).

4.4.4.2 Leaf area

In resistant variety, WGG-42 (186.75 ± 4.65), the lowest leaf area was observed.

The highest leaf area was found in susceptible variety, MGG-360 (190.29 ± 6.37) (not

significantly different) followed by moderate resistant variety, TM-962 (188.86 ± 7.22).

4.4.4.3 Leaf dry weight

The lowest leaf dry weight was observed in resistant variety, WGG-42

(1.22 ± 0.03) . The highest leaf dry weight was found in moderate resistant variety, TM-

962 (1.25 ± 0.04) and susceptible variety, MGG-360 (1.25 ± 0.04) (not significantly

different).

4.4.4.4 Leaf toughness

The lowest leaf toughness was found in moderate resistant variety, TM-962

(150.25 ± 3.35). In resistant variety, WGG-42 (152.21 ± 1.2), highest leaf toughness

was found followed by susceptible variety, MGG-360 (151.87 ± 1.29) (not significantly

different).

4.4.4.5 Chlorophyll content

In moderate resistant variety, TM-962 (39.8 ± 3.44) (significantly different),

lowest chlorophyll content was found. In resistant variety, WGG-42 (50.67 ± 4.47),

highest chlorophyll was observed followed by susceptible variety, MGG-360 (46.91 ±

3.41) (not significantly different) (Table 4.21).

4.4.4.6 Plant height

The lowest plant height was observed in susceptible variety, MGG-360 (43.2 ±

1.87) followed by resistant variety, WGG-42 (43.66 ± 0.67) (not significantly

different). The highest plant height was found in moderate resistant variety, TM-962

(45.91 ± 0.72) (significantly different).

4.4.5 Biochemical Constituents in greengram genotypes

4.4.5.1 Phenol content

Lowest amount of phenols was found in leaves of susceptible variety, MGG-360

(68.5 ± 0.22 mg/g) (significantly different). The resistant variety, WGG-42 leaves

contains more amount of phenols (69.74 ± 0.12 mg/g) followed by moderate resistant

variety, TM-962 (69.23 ± 0.12 mg/g) (significantly different) (Table 4.22).

4.4.5.2 Protein content

In resistant variety, WGG-42, lowest amount of protein (148.61 ± 0.25 mg/g)

was observed in the leaves (significantly different). The highest protein content was

observed in the leaves of susceptible variety, MGG-360 (151.46 ± 0.13 mg/g) followed

by moderate resistant variety, TM-962 (149.35 ± 0.23 mg/g) (significantly different).

4.4.5.3 Reducing sugars

The lowest amount of reducing sugars was recorded in resistant variety, WGG-

42 (25.37 ± 0.19 mg/g) (significantly different). In susceptible variety, MGG-360

(28.36 ± 0.18 mg/g), highest amount of reducing sugars was found followed by the

moderate resistant variety, TM-962 (26.32 ± 0.20 mg/g) (significantly different) (Table

4.22).

4.4.6 Correlation Study of Different Growth Parameters of M. vitrata and

Greengram Varietal Characters (Biophysical and Biochemical)

A statistical analysis was done to correlate the performance of spotted pod borer

on different genotypes of greengram with that of host plant physical and biochemical

constituents.

4.4.6.1 Number of insect larvae in each treatment after 24 hours

Larval orientation was negatively correlated with phenols (r= -0.486)

(significant at 0.05 level) and positively correlated with proteins (r=0.479 at 0.05 level)

and reducing sugars (r=0.525 at 0.05 level) (Table 4.23).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. Larval orientation could be explained by the

following regression model.

y= 13.625 – 0.186(trichome density) + 0.014(chlorophyll) – 0.04(phenols) –

0.09(proteins) + 0.191(reducing sugars) (R2=0.360).

According to the regression equation, influence of trichome density, chlorophyll

content, phenols, proteins and reducing sugars on the spotted pod borer larval

orientation was up to 36.0 % (R2=0.360) (Table 4.24).

4.4.6.2 Second instar larval duration

The larval duration of the second instar was negatively correlated with trichome

density (r= -0.776) (significant at 0.01 level).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. Second instar larval duration could be explained by

the following regression model.

y= 11.281 – 0.759(trichome density) + 0.017(chlorophyll) + 0.259(phenols) – 0.179

(proteins) + 0.205(reducing sugars) (R2= 0.718).

According to the regression equation, the second instar larval duration was

influenced by trichome density, chlorophyll content, phenols, proteins and reducing

sugars upto 71.8 % (R2=0.718).

4.4.6.3 Fourth instar larval duration

The fourth instar larval duration was positively correlated with phenols

(r=0.581) (significant at 0.01 level). Fourth instar larval duration shows negatively

correlation with proteins (r= - 0.624) and reducing sugars (r= - 0.599) (both are

significant at 0.01 level).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. The fourth instar larval duration could be explained

by the following regression model.

y=-34.416 + 0.285(trichome density) – 0.026(chlorophyll) + 0.3(phenols) –

0.402(proteins) + 0.254(reducing sugars) (R2=0.445).

The fourth instar larval duration was influenced by trichome density, chlorophyll

content, phenol, protein and reducing sugars contents upto 44.5 % (R2=0.445)

according to the regression equation.

4.4.6.4 Fifth instar larval duration

There was a positive correlation of fifth instar larval duration with phenols

(r = 0.669) (significant at 0.01 level), where as it is negatively correlated with proteins

(r= - 0.734) (significant at 0.01 level) and reducing sugars (r= -0.733) (significant at

0.01 level).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. The fifth instar larval duration could be explained

by the following regression model.

y= 67.286 + 0.257(trichome density) – 0.021(chlorophyll) – 0.201(phenols) –

0.305(proteins) – 0.199(reducing sugars) (R2=0.572).

According to the regression equation, the influence of trichome density,

chlorophyll, phenol, protein and reducing sugar contents on the fifth instar larval

duration was upto 57.2 % (R2=0.572).

4.4.6.5 Larval duration

The larval duration was positively correlated with phenols (r=0.666) (significant

at 0.01 level) and negatively correlated with proteins (r= -0.737 at 0.01) and reducing

sugars (r= - 0.730 at 0.01) .

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. The larval duration could be explained by the

following regression model.

y= 151.019 + 0.085(trichome density) – 0.015(chlorophyll) – 0.551 (phenols) – 0.586

(proteins) – 0.466(reducing sugars) (R2=0.556).

According to the regression equation, the larval duration was influenced by the

trichome density, chlorophyll, protein , phenol and reducing sugar content upto 55.6 %

(R2=0.556).

4.4.6.6 Third instar larval weight

Third instar larval weight was negatively correlated with phenols(r= - 0.783)

(significant at 0.01 level), and positively correlated with proteins (r = 0.848) (significant

at 0.01 level) and reducing sugars (r=0.857) (significant at 0.01 level).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. The third larval weight could be explained by the

following regression model.

y= -0.55 – 0.001(trichome density) – 0.0000115(chlorophyll) + 0.004(phenols) + 0.002

(proteins) + 0.003(reducing sugars) (R2=0.761).

According to the regression equation, the third instar larval weight was influenced

by trichome density, chlorophyll, phenols, proteins and reducing sugar content upto

76.1 % (R2=0.761).

4.4.6.7 Fourth instar larval weight

The fourth instar larval weight was negatively correlated with phenols (r= -

0.735) (significant at 0.01 level). Whereas, a positive correlation was observed by the

fourth instar larval weight with proteins (r=0.821) (significant at 0.01 level) and

reducing sugars (r=0.838) (significant at 0.05 level).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. The fourth instar larval weight could be explained

by the following regression model.

y= -0.372 – 0.001(trichome density) – 0.0000957(chlorophyll) + 0.004(phenols) +

0.0001 (proteins) + 0.004(reducing sugars) (R2=0.748).

According to the regression equation, the influence of trichome density,

chlorophyll, phenols, proteins and reducing sugar contents on the fourth instar larval

weight is upto 74.8 % (R2=0.748).

4.4.6.8 Pupal weight

Pupal weight was negatively correlated with phenols (r= - 0.884) (significant at

0.01 level). Whereas, a positive correlation was observed with proteins (r=0.920) and

reducing sugars (r=0.935) (both are significant at 0.01 level).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. The pupal weight could be explained by the

following regression model.

y= -0.275 – 0.001(trichome density) – 0.00000183(chlorophyll) + 0.001(phenols) +

0.001 (proteins) + 0.001(reducing sugars) (R2=0.920).

According to the regression equation, the trichome density, chlorophyll, phenols,

proteins and reducing sugars influence the pupal weight upto 92.0 % (R2=0.920).

4.4.6.9 Pupal duration

The pupal duration shows positive correlation with the phenols (r=0.936) , and

negatively correlated with proteins (r= - 0.961) and reducing sugars (r= - 0.966) (all are

significant at 0.01 level).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. The pupal duration of the spotted pod borer could

be explained by the following regression model.

y= 22.968 + 0.059(trichome density) – 0.002(chlorophyll) + 0.138(phenols) -

0.162(proteins) – 0.129(reducing sugars) (R2=0.947).

According to the regression equation, the pupal duration was influenced by

trichome dednsity, chlorophyll, phenols, proteins and reducing sugars upto 94.7 %

(R2=0.947).

4.4.6.10 Adult longevity

There was a positive correlation of adult longevity of spotted pod borer with

phenols (r=0.898) and negative correlation was observed with proteins (r = - 0.891) and

reducing sugars (r = - 0.897) (all are significant at 0.01 level) (Table 4.23).

The results of correlation studies were subjected to step wise regression analysis

to find out the regression equations. The adult longevity of the spotted pod borer could

be explained by the following regression equation.

y= 29.595 – 0.109(trichome density) + 0.028(chlorophyll) + 0.129(phenols)-

0.198(proteins)- 0.129(reducing sugars) (R2=0.877).

The adult longevity of the spotted pod borer was influenced by the trichome

density, chlorophyll, phenols, proteins and reducing sugars upto 87.7 % (R2=0.877)

(Table 4.24).

Overall influence of biophysical and biochemical constituents on spotted pod borer

performance on greengram

Trichome density

From the above results, it could be concluded that trichomes present on different

host plants had a significant negative correlation with second instar larval duration of

spotted pod borer.

It has been an established fact that pubescence or presence of trichomes confers

plant resistance to many insects including spotted pod borer larval infestation. Our

present results were in accordance with the findings of Jaydeep Halder and Srinivasan

(2011) who worked on Maruca vitrata infestation and reported that highly susceptible

variety, GC-9708 has least number of trichomes on leaves (4.8/mm2) as compared to

highly tolerant genotype HC-270 which had 9.4 trichomes/mm2. Kamakshi and

Srinivasan (2008) reported that the susceptible cultivar (USA GP 36(12-1)FB KO2) had

the least number of trichomes on pod (9.10 /mm2).

In our study, trichomes had a negative correlation with insect biological

parameters such as second instar larval duration of spotted pod borer which could be

due to the fact that presence of trichomes on plant surfaces hinders the movement of

larvae from one flower bud to the another buds as well as their feeding mechanism

which might have contributed to the findings of the present investigations.

Phenols

From our above results, it was clear that phenol had a negative significant effect

with larval orientation after 24 hours, third instar larval weights, fourth instar larval

weights, pupal weights and had a positive significant effect with fourth instar larval

duration, fifth instar larval duration, larval duration, pupal duration and adult longevity

of spotted pod borer. The results which were obtained were supported by the

observations of Anantharaju and Muthiah (2008) who reported that the LRG-41 variety

of pigeonpea shows resistance to spotted pod borer infestation and gives more yield due

to the presence of higher amounts of phenolic contents. Halder and Srinivasan (2007)

observed that the phenols were highest (21.72 mg/g) in the resistant cultivar, LBG-611

than the susceptible cultivar, LBG-17 (20.41 mg/g). Jaydeep Halder et al. (2006) have

studied and reported that the phenols were highest in the resistant cultivar LGG-497

(21.03 mg/g) than the susceptible cultivar LGG-450 (20.00 mg/g).

In our observations, phenols show positive correlation with the fourth instar

larval duration, fifth instar larval duration, larval duration, pupal duration and adult

longevity which might be the fact that due to the effect of non palatability of phenols,

the larvae spends more time for food consumption which require for normal metabolic

processes and hence the larval weights and pupal weights decreased which shows

negative correlation with the phenol content which are presented in table 4.4.7. Due to

the effect of phenols, the larvae shows negative orientation which may be due to

unpalatability of phenols.

Proteins

From the above results, it shows that the proteins have significant positive

correlation with third instar larval weight, fouth instar larval weight, pupal weights, and

significant negative correlation with fifth instar larval duration, pupal duration and adult

longevity of spotted pod borer. These results of the investigations were supported by

the Sujithra and Srinivasan (2012) observations, who reported that the highly

susceptible variety, AVT-FB(80) 15-6-4 had highest amount of protein (28.9%)as

compared to tolerant variety, TCR-137 which had 19 %of proteins. Halder and

Srinivasan (2007) observed that the highly susceptible variety, LBG-17 had the highest

amount of protein (24.3%) and the lowest values were recorded in the highly tolerant

variety, LBG-611 which had 21.6%.

Due to the palatability and availability of different amino acids from the

proteins, the duration of fourth instar larva, fifth instar larva, total instar larva, pupa

and adult completes in short period of time and hence show negative correlation with

the proteins. The larva might consume large amount of protein source and hence the

third instar larval weight, fourth instar larval weight, pupal weight and larval orientation

after 24 hours of time shows positive correlation.

Reducing sugars

It represents that the reducing sugars shows the significant positive correlation

with larval orientation after 24 hours, third instar larval weight, fouth instar larval

weight, pupal weights, and significant negative correlation with pupal duration and

adult longevity of spotted pod borer from the above obtained results. These results were

on accordance with the observations of Sujithra and Srinivasan (2012) who reported

that the highly susceptible variety, AVT-FB(80) 15-6-4 had highest amount of reducing

sugar (1.72 %) as compared to tolerant variety, TCR-137 which had 1.05 % of reducing

sugars, respectively. Halder and Srinivasan (2007) reported that the highly susceptible

variety, LBG-17 had the highest amount of reducing sugar (0.62 mg/g) and the lowest

values were recorded in the highly tolerant variety, LBG-611 which had 0.50 mg/g.

The duration of fourth instar larva, fifth instar larva, total instar larva, pupa and

adult completes in short period of time and hence show negative correlation with the

reducing sugars due to the palatability and availability of different carbohydrates from

the reducing sugars. The third instar larval weight, fourth instar larval weight, pupal

weight and larval orientation after 24 hours of time shows positive correlation with the

reducing sugars which might be the fact that the larva may continuously feed on the

source of reducing sugars which might supply the sucrose which acts as a

phagostimulant (Ramesh and Dhaliwal, 1994) .

4.5 TOLERANCE OF LARVAE OF MARUCA TO CHLORPYRIPHOS ON

RESISTANT AND SUSCEPTIBLE GENOTYPES OF BLACKGRAM AND

GREENGRAM

Insects on resistant plants tend to be smaller than insects on susceptible plants, due

to the stress imposed on them by these plants by either physical or chemical means. As

the toxicity of an insecticide depends on the body weight, lower amounts of insecticide

should be required to get the same mortality on resistant plants as that of susceptible

plants (Van Emden, 1991).

4.5.1 Blackgram

The first instar larvae were allowed to feed on the flowers and pods of resistant

and susceptible genotypes of blackgram and greengram upto third instar. A topical

bioassay was done with Chlorpyriphos at serial concentrations of 10, 5, 2.5 1.25 and

0.625 ml/lit of water, as mentioned in materaials and methods. After the 24 hours of

topical bioassay, number of dead larvae were counted to calculate the per cent mortality

(Plate 4.4). The data was subjected to probit analysis by using a statistical package

SPSS (2004) to calculate LC50 values.

From the table 4.25, it was observed that LC50 (µl/ml) and LD50 (µg/g) of

chlorpyriphos was less i.e., 1.06 µl/ml and 29.39 (µg/g) on Maruca larvae reared on

resistant blackgram genotype LBG-645 as compared to susceptible blackgram

genotype, LBG-790 i.e., 1.57 (µl/ml) and 35.72 (µg/g). This probably is due to the fact

on resistant genotype of blackgram (LBG-645) the larvae were much smaller and

weighed less (Table 4.14).due to the stress imposed on them by plant resistance factor

present in LBG-645. As the insects were much smaller, low amount of insecticide is

needed to get 50 per cent mortality and hence low LC50 values. Whereas the 3rd instar

larvae reared on susceptible blackgram genotype, LBG-790, were much bigger and

hence more dose of chemical was required to get 50 per cent mortality and hence more

LC50 values were obtained.

4.5.2 Greengram

The first instar larvae were allowed to feed on the flowers and pods of resistant

and susceptible genotypes of greengram upto third instar. A topical bioassay was done

with chlorpyriphos at serial concentrations of 10, 5, 2.5 1.25 and 0.625 ml/lit of water,

as mentioned in materaials and methods. After the 24 hours of topical bioassay number

of dead larvae were counted to calculate the per cent mortality (Plate 4.4). The data was

subjected to probit analysis by using a statistical package SPSS (2004) to calculate LC50

values.

From the table 4.26, it was clear that LC50 (µl/ml) of chlorpyriphos was less 1.39

µl/ml on Maruca larvae reared on resistant greengram genotype, WGG- 42 as

compared to susceptible greengram genotype MGG-360 (1.62 µl/ml). No significant

differences were observed in LD50 values of Chloropyriphos to M.vitrata larvae reared

on resistant and susceptible greengram genotypes. This probably is due to the fact on

resistant greengram genotype WGG-42, the larvae were much smaller and weighed less

(Table 4.16) due to the stress imposed on them by plant resistance factor present in

WGG-42. As the insects were much smaller, low amount of insecticide is needed to get

50 per cent mortality and hence low LC50 values were recorded.

The results of the investigations were strongly supported by the observations of

Muid (1977) who compared the susceptibility of an organophosphate resistant strain of

the aphid, Myzus persicae on two genotypes of Brussels sprout and reported that the

aphids were more susceptible to the chemical on the moderately resistant Brussels

sprout than on the susceptible Brussels sprout. Heinrichs et al. (1984) showed that the

LD50 (µg/g) of white backed planthopper was 9.4 on the susceptible variety, TN1

treated with ethylan, but was only 2.8 on the moderately resistant variety, N22. Attah

(1984) reported that Metopolophium dirhodum (Walker) which is a sucking insect pest

on wheat shows lower LC50 and LD50 values for insects reared on partially resistant than

on the susceptible genotypes against Malathion. Nicol et al.(1993) reported that

nymphs of wheat grain aphid reared on resistant variety, Altar were more susceptible to

deltamethrin than nymphs reared on the susceptible variety, Dollarbird.

The results of the present investigation reinstates about the importence of role of

insect resistant cultivars in managing insect pest population. Insects on resistant

cultivars would be much smaller, have slow developmental period and hence low doses

of insecticides are sufficient to achieve an effective control as against on a susceptible

cultivar that may require higher doses of insecticide to a achieve an effective control as

insects on a susceptible cultivar would be much bigger and hence fast developmental

period.

Chapter V

SUMMARY AND CONCLUSIONS

A survey was carried out in three different districts of Southern zone of Andhra

Pradesh to record per cent Maruca damage on blackgram and greengram; varieties of

blackgram and greengram popular grown; type of insecticides sprayed for managing

Maruca incidence etc. Further, studies were done on screening of different genotypes of

blackgram and greengram for susceptibility against spotted pod borer, Maruca vitrata

infestation; mechanisms of resistance involved in blackgram and greengram for spotted

pod borer and the effect of plant resistance in popular varieties of blackgram and

greengram to spotted pod borer, M.vitrata and its role in insecticide tolerance, during

2014 and 2015 in Department of Entomology, S.V. Agricultural College and Regional

Agricultural Research Station (RARS), Tirupati.

Survey on M.vitrata population in blackgram and greengram during late kharif

2014 was carried out in Chittoor, Nellore and Kadapa districts. Roving survey was

conducted and data on number of plants infested with spotted pod borer was recorded in

1 sq.mt area, to calculate the per cent damage. Information on per cent infestation,

name of the varieties of blackgram and greengram, group of insecticides used was

collected from 5 progressive farmers in each village. A total of 3 villages in each

mandal was selected for the survey. Thus a total of 27 samples were collected from 27

villages of 3 districts.

From the present investigations on the roving survey conducted, it was observed

that the per cent infestation of Maruca vitrata was more in Kadapa district in case of

both blackgram (41.99 ± 6.84) and greengram (41.1 ± 6.93) crops. The lowest per cent

infestation was observed in Chittoor (38.50 ± 5.54) in case of blackgram and in Nellore

(12.66 ± 6.54) in case of greengram. In Nellore, the per cent infestation was

39.77 ± 5.97 in case of blackgram and in case of greengram, the Chittoor district shows

a per cent infestation of 39.24 ± 5.91. In case of varietal preference by the farmers for

cultivation in all the districts, the varieties LBG-752, LBG-648, PU-31, LBG-123 and

LBG-792 occupies a range of 62.2, 1.5, 4.4, 17.8, 14.1 % in case of blackgram and the

greengram varieties LGG-460, LGG-407, LGG-480, LGG-406, PM-115 and LGG-450

occupies a per cent range of 59.3, 2.2, 2.2, 3, 11.1 and 22.2 % respectively. Among the

insecticidal usage in all the three districts, the farmers were using Chlorpyriphos.

Among the per cent insecticidal usage, Chlorpyriphos occupies more than the 50 %

against the spotted pod borer infestation in both blackgram and greengram crops.

Nine genotypes of blackgram viz., LBG-709, PU-31, LBG-20, LBG-790,

LBG-752, LBG-792, LBG-123, LBG-791 and LBG-645 and ten genotypes of

greengram viz., WGG-42, LGG-407, PM-115, MGG-360, PM-110, LGG-410, PM-112,

TM-962, LGG-450 and LGG-460 were screened for their susceptibility to spotted pod

borer infestation at wetland farm, S.V.Agricultural College, Tirupati. Readings on the

number of Maruca webbings per plant, total number of caterpillars per plant and per

cent infestation were taken at weekly intervals.

From the results of investigation, the genotypes viz., LBG-645, LBG-791 and

LBG-790 were classified as resistant, moderate resistant and susceptible genotypes of

blackgram and the genotypes viz., WGG-42, TM-960 and MGG-360 were classified as

resistant, moderate resistant and susceptible genotypes of greengram based on number

of webbings per plant and total number of caterpillars per plant. The blackgram

genotypes viz., LBG-645, LBG-791 and LBG-790 had 2.02 ± 0.50, 2.83 ± 0.62 and

4.60 ± 1.00 number of Maruca webbings per plant for one planting and the greengram

genotypes viz., WGG-42, TM-960 and MGG-360 had 2.28 ± 0.50, 3.85 ± 0.68 and 5.83

± 0.54 number of Maruca webbings per plant in first planting and 2.38 ± 0.63, 3.53 ±

0.84 and 5.33 ± 0.67 number of webbings per plant in second planting. The blackgram

genotypes viz., LBG-645, LBG-791 and LBG-790 had 1.62 ± 0.59, 2.70 ± 0.62 and

4.07 ± 0.74 number of caterpillars per plant for one planting and the greengram

genotypes viz., WGG-42, TM-960 and MGG-360 had 1.73 ± 0.52, 3.11 ± 0.82 and 6.08

± 0.87 number of caterpillars per plant in first planting and 1.84 ± 0.54, 3.23 ± 0.69 and

5.02 ± 0.84 number of Maruca caterpillars per plant in second planting.

Genotypes of blackgram and greengram that were selected from field screening

were further investigated in the laboratory through free-choice technique and biology

study. In larval free choice experiment of blackgram, it was observed that more number

of larvae of Maruca preferred the genotype LBG-790 (2.57 ± 0.98) (susceptible) which

were significantly different from LBG-645 (resistant) which were preferred by few

number of Maruca larvae (1.57 ± 0.54). Larval preference of variety LBG-791 (1.86 ±

0.69) (moderate resistant) was in between LBG-790 and LBG-645. The results of

investigation of the biology of Maruca in blackgram infers that there is no significant

difference in second instar and third instar larval duration in all the genotypes. The

duration of the fourth instar larva was less on LBG-790 (2.43 ± 0.54 days)

(susceptible) followed by 2.57 ± 0.54 days on LBG-791 (on par with) (moderate

resistant) . Highest larval duration (3.00 ± 0.54 days) of fourth instar was observed

when larvae were reared on LBG-645 (resistant). The duration of the fifth instar larva

was least 2.86 ± 0.54 days when larvae were reared on LBG-790 (susceptible) followed

by 3.00 ± 0.54 days on LBG-645 (resistant) and 3.57 ± 0.54 days on LBG-791

(moderate resistant). The total duration of the larvae was least (11.86 ± 0.54 days) on

LBG-790 (susceptible) followed by 12.71 ± 0.54 days in LBG-791 (moderate resistant)

and 13.00 ± 0.54 days in LBG-645 (resistant). The lowest larval weight of the third

instar (0.0325 ± 0.019 gms) was observed, when larvae were reared on LBG-645

(resistant) followed by 0.0362 ± 0.0022 gms on LBG-791 (moderate resistant). Highest

larval weights (0.0418 ± 0.0058 gms) were observed, when larvae were reared on LBG-

790 (susceptible) genotype. The lowest larval weight of the fourth instar (0.0449 ±

0.0021 gms) was observed when larvae were reared on LBG-645 (resistant) followed

by (0.0483 ± 0.0013 gms) on LBG-791 (moderate resistant). Highest larval weights of

fourth instar was observed as 0.0556 ± 0.0053 gms, when larvae were reared on LBG-

790 (susceptible). The pupal weight was lowest (0.0398 ± 0.0021 gms) when they were

reared on LBG-645 (resistant) followed by LBG-791 (moderate resistant) (0.0422 ±

0.0021 gms). Highest pupal weights were observed, when the insects were reared on

LBG-790 (susceptible) (0.0447 ± 0.0033 gms). The duration of the pupae was

4.52 ± 0.5 days on LBG-790 (susceptible) followed by 5.21 ± 0.47 days on LBG-791

(moderate resistant) and 5.57 ± 0.54 days in LBG-645 (resistant) varieties. The

longevity of the adults was 4.98 ± 0.56 days on LBG-790 (susceptible) followed by

5.79 ± 0.64 days on LBG-791 (moderate resistant). Highest adult longevity was

observed 6.45 ± 0.59 days, when insects were reared on LBG-645 (resistant).

In case of greengram genotypes, it was observed that more number of larvae of

Maruca preferred the genotype MGG-360 (2.57 ± 0.79) (susceptible) which were

significantly different from WGG-42 (resistant) which were preferred by few number of

Maruca larvae (1.57 ± 0.53). Larval preference of genotype TM-962 (1.86 ± 0.69)

(moderate resistant) were in between MGG-360 and WGG-42. The study of biology on

greengram genotypes revealed that the duration of the second instar larva of spotted

pod borer is 3.00 ± 0.00 days, when reared on MGG-360 (susceptible) followed by 3.14

± 0.38 days on WGG-42 (resistant) and 3.57 ± 0.53 days in TM-962 (moderate

resistant) genotypes. The duration of third instar larva was 3.29 ± 0.49 days on TM-962

(moderate resistant) followed by 3.43 ± 0.53 days in MGG-360 (susceptible) and 3.71 ±

0.49 days in WGG-42 (resistant). The duration of the fourth instar larva was 2.14 ± 0.38

days on MGG-360 (susceptible) followed by 2.71 ± 0.49 days in TM-962 (moderate

resistant) and 2.86 ± 0.38 days on WGG-42 (resistant). The duration of the fifth instar

larva was 2.57 ± 0.53 days on MGG-360 (susceptible) (significantly different) followed

by 3.43 ± 0.53 days on TM-962 (moderate resistant) and 3.71 ± 0.49 days on WGG-42

(resistant). The total duration of the larvae was 11.14 ± 1.21 days on MGG-360

(susceptible) followed by 13.00 ± 1.15 days on TM-962 (moderate resistant) and 13.43

± 0.53 days on WGG-42 (resistant). The lowest larval weight of the third instar (0.0342

± 0.0018 gms) was observed, when larvae were reared on WGG-42 (resistant) followed

by 0.0380 ± 0.0035 gms on TM-962 (moderate resistant). Highest larval weights

(0.0440 ± 0.0021 gms), were observed, when larvae were reared on MGG-360

(susceptible). The lowest larval weight of the third instar (0.0444 ± 0.0026 gms) was

observed, when larvae were reared on WGG-42 (resistant) followed by 0.0459 ± 0.0031

gms on TM-962 (moderate resistant). Highest larval weights (0.0525 ± 0.0016 gms)

were observed when larvae were reared on MGG-360 (susceptible). Lowest pupal

weight (0.0397 ± 0.0020) were observed, when insects were reared on WGG-42

(resistant) followed by TM-962 (moderate resistant) (0.0425 ± 0.0019) and (0.0468 ±

0.0012) gms, when insects were reared on MGG-360 (susceptible). The duration of the

pupa was 4.52 ± 0.5 days on MGG-360 (susceptible) followed by 5.21 ± 0.47 days in

TM-962 (moderate resistant) and 5.55 ± 0.55 days on WGG-42 (resistant) genotypes.

The longivity of the adults was 5.21 ± 0.52 days on MGG-360 (susceptible) followed

by 5.79 ± 0.64 days on TM-962 (moderate resistant) and 6.45 ± 0.6 days on WGG-42

(resistant).

The physical and biochemical constituents of the genotypes of blackgram and

greengram and their correlation and regression studies with the spotted pod borer were

carried in the laboratory. From the results of investigation, in blackgram genotypes the

lowest trichome density was observed in case of LBG-791 (37.43 ± 4.28) (moderate

resistant). The highest trichome density was found in LBG-645 (41.57 ± 4.04)

(resistant) followed by LBG-790 (39.71 ± 2.63) (susceptible). The lowest leaf area was

reported in LBG-790 (156.29 ± 4.57) (susceptible). The highest leaf area was found in

LBG-645(159.71 ± 3.55) (resistant) followed by LBG-791 (159.43 ± 4.50). The lowest

leaf dry weight was recorded in LBG-790 (0.72 ± 0.04) (susceptible). The highest leaf

dry weight was observed in LBG-645 (0.75 ± 0.03)(resistant) followed by LBG-791

(0.74 ± 0.04) (moderate resistant). Leaf toughness is less in LBG-645 (210.88 ± 4.03)

(resistant). The highest leaf toughness was recorded in LBG-790 (215.65 ± 5.48)

(susceptible) followed by LBG-791 (214.43 ± 5.53) (moderate resistant). The lowest

chlorophyll content was found in resistant genotype, LBG-645 (36.4 ± 4.87). The

highest chlorophyll content was observed in susceptible genotype, LBG-790

(48.75 ± 3.15) followed by moderate resistant genotype, LBG-791 (44.9 ± 2.26). The

plant height was observed to be lowest in susceptible genotype, LBG-790

(34.88 ± 1.84). The plant height was found to be highest in resistant genotype,

LBG-645 (35.36 ± 1.64) followed by moderate resistant genotype, LBG-791

(35.1 ± 2.03). Lowest amount of phenols was found in leaves of susceptible genotype,

LBG-790 (68.55 ± 0.38 mg/g). The resistant genotype, LBG-645 leaves contains more

amount of phenols (70.37 ± 0.21 mg/g) followed by moderate resistant genotype,

LBG-791 (69.27 ± 0.26 mg/g). In resistant genotype, LBG-645, lowest amount of

protein (148.52 ± 0.46 mg/g) was observed in the leaves (significantly different). The

highest protein content was observed in the leaves of susceptible genotype, LBG-790

(151.92 ± 0.73 mg/g) followed by moderate resistant genotype, LBG-791

(149.97 ± 0.72 mg/g). The lowest amount of reducing sugars was recorded in resistant

genotype, LBG-645 (25.2 ± 0.35 mg/g). In susceptible genotype, LBG-790, highest

amount of reducing sugars (31.71 ± 0.37 mg/g) was found followed by the moderate

resistant genotype, LBG-791 (26.31 ± 0.38 mg/g).

The number of larvae in each treatment i.e., larval orientation was negatively

correlated with total phenol content (r= -0.537) of different varieties of blackgram and

positively correlated with reducing sugars (r=0.486). The influence of trichome density,

chlorophyll, phenols, proteins and reducing sugars on larval orientation is upto 35.1 %

(R2=0.351). Fourth instar larval duration was negatively correlated with chlorophyll

content (r= - 0.502) and positively correlated with phenols (r=0.522). The influence of

trichome density, chlorophyll content, phenols, proteins and reducing sugars content on

fourth instar larval duration is upto 34.7% (R2=0.347). Third instar larval weight was

negatively correlated with phenols (r= -0.667). Whereas, a positive correlation was

observed with chlorophyll (r=0.556), proteins (r=0.691) and reducing sugars (r=0.693).

The influence of trichome density, chlorophyll content, phenols, proteins and reducing

sugars on fourth instar larval weight is upto 53% (R2=0.530). Fourth instar larval

weight was negatively correlated with phenols (r= -0.733 at 0.01 level). Whereas, a

positive correlation was found with chlorophyll content(r=0.629 at 0.01 level), proteins

(r=0.812 at 0.01) and reducing sugars (r=0.809 at 0.01). The influence of trichome

density, chlorophyll content, proteins, phenols and reducing sugars on fourth instar

larval weight is upto 70.1 % (R2=0.701). Pupal weight was positively correlated with

chlorophyll content (r=0.545 at 0.05), proteins (r=0.767 at 0.01), reducing sugars

(r=0.744 at 0.01). Whereas, a negative correlation was found with phenols (r= - 0.665).

The influence of trichome density, chlorophyll content, phenols, proteins and reducing

sugars on pupal weight is upto 61.3 % (R2=0.613). Pupal duration was positively

correlated with phenols (r=0.904). Whereas, a negative correlation was observed with

chlorophyll content (r= -0.721), proteins (r= -0.892) and reducing sugars (r= -0.959).

The influence of chlorophyll content, phenols, proteins and reducing sugars is upto 96.6

% (R2=0.966). Adult longivity was negatively correlated with chlorophyll content

(r= -0.811), proteins (r= -0.885) and reducing sugars (r= -0.906). Whereas, a positive

correlation was observed with phenols (r=0.900). The influence of trichome density,

chlorophyll content, phenols, proteins and reducing sugars on adult longevity is upto

88.6 % (R2=0.886).

From the results of investigation, in greengram varieties the lowest trichomes

was observed in moderate resistant genotype, TM-962 (44.86 ± 6.18). Highest

trichomes was found in resistant genotype, WGG-42 (55.29 ± 6.75) followed by

susceptible genotype, MGG-360 (52.71 ± 5.25). In resistant genotype, WGG-42

(186.75 ± 4.65), the lowest leaf area was observed. The highest leaf area was found in

susceptible genotype, MGG-360 (190.29 ± 6.37) followed by moderate resistant

genotype, TM-962 (188.86 ± 7.22). The lowest leaf dry weight was observed in

resistant genotype, WGG-42 (1.22 ± 0.03) . The highest leaf dry weight was found in

moderate resistant variety, TM-962 (1.25 ± 0.04) and susceptible variety, MGG-360

(1.25 ± 0.04). The lowest leaf toughness was found in moderate resistant variety, TM-

962 (150.25 ± 3.35). In resistant variety, WGG-42 (152.21 ± 1.2), highest leaf

toughness was found followed by susceptible variety, MGG-360 (151.87 ± 1.29). In

moderate resistant variety, TM-962 (39.8 ± 3.44), lowest chlorophyll content was

found. In resistant variety, WGG-42 (50.67 ± 4.47), highest chlorophyll was observed

followed by susceptible genotype, MGG-360 (46.91 ± 3.41). The lowest plant height

was observed in susceptible genotype, MGG-360 (43.2 ± 1.87) followed by resistant

genotype, WGG-42 (43.66 ± 0.67). The highest plant height was found in moderate

resistant genotype, TM-962 (45.91 ± 0.72). Lowest amount of phenols was found in

leaves of susceptible genotype, MGG-360 (68.5 ± 0.22 mg/g). The resistant genotype,

WGG-42 leaves contains more amount of phenols (69.74 ± 0.12 mg/g) followed by

moderate resistant genotype, TM-962 (69.23 ± 0.12 mg/g). In resistant genotype,

WGG-42, lowest amount of protein (148.61 ± 0.25 mg/g) was observed in the leaves.

The highest protein content was observed in the leaves of susceptible genotype, MGG-

360 (151.46 ± 0.13 mg/g) followed by moderate resistant genotype, TM-962 (149.35 ±

0.23 mg/g). The lowest amount of reducing sugars was recorded in resistant genotype,

WGG-42 (25.37 ± 0.19 mg/g). In susceptible genotype, MGG-360 (28.36 ± 0.18 mg/g),

highest amount of reducing sugars was found followed by the moderate resistant

genotype, TM-962 (26.32 ± 0.20 mg/g).

Larval orientation was negatively correlated with phenols (r= -0.486)

(significant at 0.05 level) and positively correlated with proteins (r=0.479 at 0.05 level)

and reducing sugars (r=0.525 at 0.05 level). The influence of trichome density,

chlorophyll content, phenols, proteins and reducing sugars on the spotted pod borer

larval orientation was up to 36.0 % (R2=0.360). The larval duration of the second instar

was negatively correlated with trichome density (r= -0.776). The second instar larval

duration was influenced by trichome density, chlorophyll content, phenols, proteins and

reducing sugars upto 71.8 % (R2=0.718). The fourth instar larval duration was

positively correlated with phenols (r=0.581). Fourth instar larval duration shows

negatively correlation with proteins (r= -0.624) and reducing sugars (r= -0.599). The

fourth instar larval duration was influenced by trichome density, chlorophyll content,

phenol, protein and reducing sugars contents upto 44.5 % (R2=0.445). There was a

positive correlation of fifth instar larval duration with phenols (r =0.669), where as it is

negatively correlated with proteins (r= -0.734) (significant at 0.01 level) and reducing

sugars (r= -0.733). The influence of trichome density, chlorophyll, phenol, protein and

reducing sugar contents on the fifth instar larval duration was upto 57.2 % (R2=0.572).

The larval duration was positively correlated with phenols (r=0.666) and negatively

correlated with proteins (r= -0.737 at 0.01) and reducing sugars (r= -0.730 at 0.01). The

larval duration was influenced by the trichome density, chlorophyll, protein , phenol

and reducing sugar content upto 55.6 % (R2=0.556). Third instar larval weight was

negatively correlated with phenols(r= -0.783), and positively correlated with proteins

(r=0.848) and reducing sugars (r=0.857). The third instar larval weight was influenced

by trichome density, chlorophyll, phenols, proteins and reducing sugar content upto

76.1 % (R2=0.761). The fourth instar larval weight was negatively correlated with

phenols (r= -0.735). Whereas, a positive correlation was observed by the fourth instar

larval weight with proteins (r=0.821) and reducing sugars (r=0.838). The influence of

trichome density, chlorophyll, phenols, proteins and reducing sugar contents on the

fourth instar larval weight is upto 74.8 % (R2=0.748). Pupal weight was negatively

correlated with phenols (r=-0.884). Whereas, a positive correlation was observed with

proteins (r=0.920) and reducing sugars (r=0.935). The trichome density, chlorophyll,

phenols, proteins and reducing sugars influence the pupal weight upto 92.0 %

(R2=0.920). The pupal duration shows positive correlation with the phenols (r=0.936),

and negatively correlated with proteins (r= -0.961) and reducing sugars (r= - 0.966).

The pupal duration was influenced by trichome density, chlorophyll, phenols, proteins

and reducing sugars upto 94.7 % (R2=0.947). There was a positive correlation of adult

longevity of spotted pod borer with phenols (r=0.898) and negative correlation was

observed with proteins (r= -0.891) and reducing sugars (r = -0.897). The adult longevity

of the spotted pod borer was influenced by the trichome density, chlorophyll, phenols,

proteins and reducing sugars upto 87.7 % (R2=0.877).

Larvae of the first instar were allowed to feed on the susceptible and resistant

varieties of the blackgram and greengram upto third instar. At the third instar stage,

they were allowed for topical bioassay application with Chlorpyriphos insecticide after

taking the larval weights. In blackgram, the larvae which fed on the LBG-645

(resistant) gave lower LC50 and LD50 values of 1.06 µL/ml and 29.39 µg/g and the

larvae which fed on the LBG-790 (susceptible) gave higher LC50 and LD50 values of

1.57 µL/ml and 35.72 µg/g. In greengram, the larvae which fed on the WGG-42

(resistant) gave LC50 and LD50 values of 1.39 µL/ml and 36.98 µg/g and the larvae

which fed on the MGG-360 (susceptible) gave LC50 and LD50 values of 1.63 µL/ml and

36.85 µg/g.

Conclusions

1. From the survey, it was found that per cent Maruca infestation was more in

Kadapa district followed by Nellore and Chittoor districts.

2. In all the three districts surveyed, blackgram genotype LBG 752 and greengram

genotype LGG 460 was preferred by most of the farmers.

3. Chlorpyriphos was preferred by most of the farmers for managing Maruca

infestation in both blackgram and greengram.

4. Observations from field screening experiments revealed that blackgram

genotypes LBG 645, LBG 791 and LBG 790 showed resistant, moderately

resistant and susceptible reaction to Maruca infestation.

5. Green gram genotypes WGG 42, TM 960 and MGG 360 showed resistant,

moderately resistant and susceptible reaction to Maruca infestation.

6. Further investigation on biology of Maruca on selected genotypes of blackgram

and greengram in the laboratory to confirm the resistance ranking observed in

the field screening, have yielded similar resistance reaction to Maruca

infestation.

7. Studies on correlation between biophysical and biochemical constituents of the

blackgram and greengram genotypes with that of insect growth parameters,

have revealed following results

Larval orientation had a positive correlation with proteins and reducing

sugars.

Chlorophyll content showed a positive correlation with weights of larvae

and pupae and negative correlation with the duration of pupae and adult.

Phenols showed a positive correlation with the duration of the larvae,

pupae and adults and negative correlation with the weight of the larvae

and pupae.

Proteins and reducing sugars showed a negative correlation with the

duration of the larvae, pupae and adults and positive correlation with the

weight of the larvae and pupae.

8. Studies on topical bioassay with chlorpyriphos revealed that the larvae reared on

resistant genotypes of blackgram and greengram had lower LC50 and LD50

values as compared to larvae reared on susceptible genotypes of blackgram and

greengram.

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---

Plate 4.1a. Collecting information from the farmer

--

Plate 4.1b. Conducting Roving survey in farmers field

a. Overall view of field layout

b. Flower webbing c. Pod webbing

Plate 4.2 Screening of blackgram and greengram genotypes for Maruca infestation

Plate 3.1. Mass multiplication of spotted pod borer

a. Cannibalism in spotted pod borer

b. Rearing of individual larva in six

well cell culture cluster

c. Pupa and Adult of spotted pod borer d. Ovipositional cages for adult rearing

e. Eggs on underside of the leaf

f. Emergence of 1st instar larva

a. Topical bioassay application of Chloripyriphos insecticide

b. Dead larvae after Chloripyriphos topical application

Plate 4.4. Insecticidal resistance by topical bioassay studies

a. Larval preference by free-choice technique

b. Biology studies by no-choice technique

Plate 4.3. Biology studies on different genotypes by free-choice and no-choice

techniques

Table 4.1. Percentage infestation of Maruca vitrata in different districts of southern

zone of Andhra Pradesh

Blackgram

S. No District Mean ± S.D

1 Nellore 39.77 ± 5.97

2 Kadapa 41.99 ± 6.84

3 Chittore 38.50 ± 5.54

Grand Mean 40.08 ± 6.26

C.V(%) 15.32

Greengram

S. No District Mean ± S.D

1 Nellore 12.66 ± 6.54

2 Kadapa 41.1 ± 6.93

3 Chittore 39.24 ± 5.91

Grand Mean 41.00 ± 6.58

C.V(%) 15.80

Table 4.2. Varieties preferred by the farmers in southern zone districts of Andhra

Pradesh

Blackgram

S.No Varieties % Grown

1 LBG-752 62.2%

2 LBG-648 1.5%

3 PU-31 4. 4%

4 LBG-123 17.8%

5 LBG-792 14.1%

Total(%) 100

Greengram

S.No Varieties % Grown

1 LGG-460 59.3%

2 LGG-407 2.2%

3 LGG-480 2.2%

4 LGG-406 3%

5 PM-115 11.1%

6 LGG-450 22.2%

Total(%) 100

Table 4.3. Insecticide usage by the farmers of southern zone of Andhra Pradesh

against Maruca vitrata infestation

Blackgram

S.No Insecticide % Usage

1 chloropyriphos 51.9

2 acephate 9.6

3 DDVP 8.9

4 novluron 20.7

5 quinalphos 4.4

6 thiodicarb 4.4

Total(%) 100

Greengram

S.No Insecticide % Usage

1 chloropyriphos 54.1

2 acephate 8.1

3 DDVP 17.8

4 novluron 14.8

5 quinalphos 0.7

6 thiodicarb 4.4

Total(%) 100

Table 4.8. Total number of M.vitrata caterpillars per plant in different genotypes of greengram

DAS

Genotype

71 DAS 78 DAS 85 DAS 92 DAS Mean

WGG-42 1.00a±0.00

(1.41)

1.07a±0.88

(1.41)

3.67a±1.11

(1.89)

1.20a±0.94

(1.45)

1.73a±0.52

(1.54)

LGG-407 1.07a±0.70

(1.42)

2.13b±0.99

(1.75)

6.07b±1.28

(2.45)

2.93b±1.90

(1.93)

3.05b±0.94

(1.89)

PM-115 1.27a±0.59

(1.50)

2.27bc±0.88

(1.79)

5.60b±1.24

(2.35)

3.73b±1.71

(2.13)

3.21b±0.65

(1.94)

MGG-360 3.20b±0.86

(2.04)

6.53d±2.47

(2.71)

7.87c±1.12

(2.80)

6.73c±2.52

(2.75)

6.08c±0.87

(2.57)

PM-110 0.87a±0.74

(1.34)

2.47bc±1.40

(1.83)

5.80b±1.74

(2.38)

3.33b±1.54

(2.05)

3.11b±0.90

(1.90)

LGG-410 0.87a±0.64

(1.35)

3.33c±1.71

(2.05)

6.13b±1.64

(2.46)

3.33b±1.17

(2.06)

3.41b±1.01

(1.98)

PM-112 1.20a±0.77

(1.46)

2.73bc±1.28

(1.91)

5.33b±1.11

(2.30)

4.13b±1.88

(2.23)

3.35b±0.91

(1.97)

TM-962 1.33a±1.04

(1.50)

1.73ab±1.16

(1.62)

5.80b±1.14

(2.40)

3.60b±1.92

(2.10)

3.11b±0.82

(1.90)

LGG-450 1.00a±0.65

(1.39)

2.00ab±0.92

(1.71)

5.67b±1.39

(2.36)

3.27b±1.90

(2.02)

2.98b±0.83

(1.87)

LGG-460 1.33a±0.72

(1.51)

2.27bc±0.88

(1.79)

5.67b±1.44

(2.36)

3.07b±1.90

(1.96)

3.08b±0.80

(1.91)

Grand Mean 1.31±0.95

(1.49)

2.65±1.92

(1.86)

5.76±1.62

(2.38)

3.53±2.17

(2.07)

3.31±1.31

(1.95)

Values in parenthesis are square root transformed

Values having the same alphabet are not significantly different as per DMRT.

Table 4.7. Number of webbings of M.vitrata larva per plant in different genotypes of greengram

DAS

Genotypes

71 DAS 78 DAS 85 DAS 92 DAS Mean

WGG-42 1.07a±0.25

(1.03)

2.53a±0.83

(1.57)

2.60a±0.73

(1.60)

2.93a±0.88

(1.70)

2.28a±0.50

(1.47)

LGG-407 1.40ab±0.63

(1.16)

4.20b±1.01

(2.04)

4.60bc±0.98

(2.13)

5.00b±1.64

(2.21)

3.80b±0.77

(1.88)

PM-115 1.47ab±0.74

(1.18)

3.87b±0.99

(1.95)

3.93b±1.03

(1.97)

4.47b±1.40

(2.09)

3.43b±0.72

(1.80)

MGG-360 2.73c±0.88

(1.63)

5.87c±1.18

(2.41)

6.93d±1.10

(2.63)

7.80d±1.14

(2.79)

5.83d±0.54

(2.36)

PM-110 1.27ab±0.45

(1.11)

4.27b±1.58

(2.03)

4.73bc±1.03

(2.16)

5.00b±1.25

(2.22)

3.81b±0.75

(1.88)

LGG-410 1.33ab±0.48

(1.14)

5.67c±1.87

(2.35)

5.07c±1.22

(2.23)

6.20c±1.42

(2.47)

4.56c±1.04

(2.05)

PM-112 1.53ab±0.64

(1.21)

4.27b±1.90

(2.01)

4.73bc±1.57

(2.14)

5.33bc±1.49

(2.29)

3.96b±1.21

(1.92)

TM-962 1.67b±0.81

(1.26)

4.07b±1.10

(2.00)

4.47bc±0.90

(2.15)

5.00b±1.60

(2.21)

3.85b±0.68

(1.90)

LGG-450 1.33ab±0.48

(1.14)

3.47ab±1.06

(1.84)

4.00b±1.06

(1.98)

4.60b±1.40

(2.12)

3.35b±0.73

(1.77)

LGG-460 1.40ab±0.63

(1.16)

3.87b±1.56

(1.93)

4.60bc±6.91

(2.13)

4.93b±1.22

(2.20)

3.70b±0.78

(1.86)

Grand Mean 1.52±0.74

(1.20)

4.21±1.60

(2.01)

4.59±1.46

(2.11)

5.13±1.77

(2.23)

3.86±1.16

(1.89)

Values in parenthesis are square root transformed values

Values having the same alphabet are not significantly different as per DMRT.

Table 4.9. Percentage infestation of M.vitrata in different genotypes of greengram

DAS

Genotypes

Total no. of

plants 71 DAS 78 DAS 85 DAS 92 DAS Mean

WGG-42 18.67a±3.05

(4.31)

32.70a±5.14

(34.85)

37.58a±1.26

(37.83)

37.58a±1.26

(37.83)

37.58a±1.26

(37.83)

36.36a±1.96

(37.08)

LGG-407 20.67ab±3.51

(4.53)

26.07a±2.95

(30.70)

46.39abc±11.09

(42.93)

44.80ab±12.14

(42.01)

44.80ab±12.14

(42.01)

40.52ab±9.50

(39.41)

PM-115 20.33ab±0.57

(4.51)

27.93a±6.14

(31.84)

44.20ab±3.87

(41.69)

45.79ab±6.22

(42.60)

50.79bc±5.18

(45.48)

42.18ab±4.08

(40.40)

MGG-360 21.00ab±1.00

(4.58)

25.51a±3.92

(30.31)

57.07c±2.04

(49.10)

63.43c±3.33

(52.83)

65.10d±1.51

(53.82)

52.78c±0.69

(46.52)

PM-110 22.33ab±2.88

(4.72)

25.80a±5.41

(30.46)

41.15ab±10.15

(39.86)

43.93ab±7.81

(41.51)

45.32abc±6.33

(42.33)

39.05ab±7.21

(38.54)

LGG-410 22.67ab±1.52

(4.76)

25.30a±6.97

(30.09)

36.91a±7.22

(37.37)

35.46a±5.47

(36.53)

38.510ab±8.08

(38.30)

34.04a±6.05

(35.57)

PM-112 20.67ab±2.30

(4.54)

25.92a±2.78

(30.60)

53.36bc±2.95

(46.96)

53.36bc±2.95

(46.96)

56.73cd±3.79

(48.90)

47.34bc±2.36

(43.35)

TM-962 22.67ab±0.57

(4.76)

25.03a±2.91

(30.01)

44.07ab±3.49

(41.6)

47.03ab±8.80

(43.31)

47.03abc±8.80

(43.31)

40.79ab±5.50

(39.56)

LGG-450 22.33ab±2.88

(4.72)

24.41a±6.20

(29.52)

45.68abc±10.77

(42.52)

48.46ab±8.42

(44.14)

48.46abc±8.48

(44.14)

41.75ab±8.42

(40.08)

LGG-460 21.47b±2.08

(4.83)

25.85a±2.40

(30.56)

38.73a±4.88

(38.48)

41.45ab±3.47

(40.09)

41.45ab±3.47

(40.09)

36.87ab±3.13

(37.31)

Grand Mean 21.47±2.34

(4.63)

26.45±4.57

(30.90)

44.51±8.50

(41.84)

46.13±9.53

(42.78)

47.57±9.86

(43.62)

41.17±7.06

(39.78)

Values in parenthesis are arc sine transformed values

Values having the same alphabet are not significantly different as per DMRT

Table 4.11. Total number of M.vitrata caterpillars per plant in different genotypes of greengram

DAS

Genotypes

57 DAS 64 DAS 71 DAS 78 DAS 85 DAS 92 DAS Mean

WGG-42 0.73ab±0.59

(1.30)

0.93a±0.88

(1.36)

3.27a±1.16

(1.78)

2.07a±1.48

(1.69)

2.27a±1.62

(1.75)

1.87a±0.83

(1.34)

1.84a±0.54

(1.54)

LGG-407 0.93ab±0.70

(1.37)

2.00ab±1.51

(1.68)

4.67b±1.58

(2.13)

3.80b±1.97

(2.14)

6.20c±1.89

(2.66)

2.60ab±1.05

(1.58)

3.36b±0.68

(1.93)

PM-115 0.87ab±0.74

(3.14)

2.40b±1.50

(1.8)

4.80b±1.20

(2.17)

5.13b±1.59

(2.45)

5.40bc±1.63

(2.51)

2.47ab±1.12

(1.53)

3.45b±0.81

(1.97)

MGG-360 1.80c±0.67

(1.66)

2.20b±1.61

(1.74)

6.40c±2.06

(2.48)

6.60c±2.02

(2.73)

8.20d±2.67

(3.01)

4.93c±1.28

(2.20)

5.02c±0.84

(2.30)

PM-110 0.53a±0.51

(1.22)

2.20b±1.01

(1.77)

4.40ab±1.45

(2.07)

4.27b±1.83

(2.26)

4.87bc±1.84

(2.39)

3.07b±1.33

(1.71)

3.20b±0.58

(1.90)

LGG-410 1.07b±0.70

(1.42)

2.27b±1.83

(1.74)

4.73b±1.66

(2.14)

3.87b±1.80

(2.16)

5.27bc±1.66

(2.48)

2.60ab±0.98

(1.58)

3.30b±0.74

(1.92)

PM-112 0.73ab±0.45

(1.30)

2.80b±1.37

(1.92)

4.40ab±1.72

(2.06)

3.80b±1.52

(2.16)

4.20b±1.74

(2.25)

3.07b±1.16

(1.72)

3.14b±0.63

(1.90)

TM-962 0.67ab±0.48

(1.28)

2.27b±1.38

(1.71)

4.27ab±1.03

(2.05)

3.93b±1.33

(2.23)

5.40bc±1.40

(2.51)

3.07b±1.33

(0.71)

3.23b±0.69

(1.91)

LGG-450 1.13b±0.64

(1.44)

1.93ab±1.16

(1.68)

4.40ab±1.50

(2.07)

2.47a±1.12

(1.83)

5.40bc±3.26

(2.45)

2.33ab±0.81

(1.50)

2.94b±0.80

(1.83)

LGG-460 0.80ab±0.56

(1.32)

2.00ab±1.25

(1.69)

4.20ab±1.58

(2.01)

4.53b±1.64

(2.33)

4.73bc±1.94

(2.36)

2.60ab±1.29

(1.57)

3.14b±0.83

(1.88)

Grand Mean 0.93±0.68

(1.37)

2.08±1.41

(1.71)

4.55±1.65

(2.10)

4.05±2.01

(2.20)

5.19±2.43

(2.44)

2.86±1.35

(1.65)

3.26±1.01

(1.91)

Values in parenthesis are square root transformed values

Values having the same alphabet are not significantly different as per DMRT.

Table 4.10. Number of webbings of M.vitrata larva per plant in different genotypes of greengram

DAS

Genotypes

57 DAS 64 DAS 71 DAS 78 DAS 85 DAS 92 DAS Mean

WGG-42 1.07a±0.25

(1.03)

1.93a±0.79

(1.36)

2.67a±0.97

(1.61)

2.80a±0.94

(1.65)

2.93a±1.22

(1.68)

2.87a±0.91

(1.67)

2.38a±0.63

(1.50)

LGG-407 1.47a±0.74

(1.18)

2.33abc±1.29

(1.47)

3.73b±1.33

(1.9)

4.67d±1.49

(2.13)

5.33c±1.39

(2.29)

5.73b±1.28

(2.38)

3.86b±0.97

(1.89)

PM-115 1.47a±0.64

(1.19)

2.67abc±1.11

(1.60)

3.80b±0.94

(1.93)

4.40cd±0.91

(2.09)

4.93bc±1.03

(2.21)

4.87b±1.45

(2.18)

3.70b±0.69

(1.87)

MGG-360 2.27b±0.88

(1.48)

3.20c±1.52

(1.74)

5.20c±1.20

(2.27)

6.20e±0.86

(2.48)

7.47d±0.91

(2.73)

7.80c±1.01

(2.79)

5.33c±0.67

(2.25)

PM-110 1.27a±0.59

(1.10)

2.27ab±0.88

(1.48)

3.60b±0.98

(1.88)

4.27cd±1.10

(2.05)

4.53bc±1.40

(2.10)

4.93b±1.28

(2.20)

3.47b±0.65

(1.80)

LGG-410 1.40a±0.63

(1.16)

2.60abc±1.18

(1.57)

3.73b±1.16

(1.91)

3.93bcd±1.22

(1.96)

4.93bc±1.33

(2.20)

5.20b±1.01

(2.27)

3.62b±0.84

(1.84)

PM-112 1.27a±0.45

(1.11)

2.93bc±1.16

(1.68)

3.27ab±1.48

(1.77)

3.07ab±0.79

(1.74)

4.27b±1.22

(2.04)

4.80b±1.01

(2.18)

3.27b±0.71

(1.75)

TM-962 1.20a±0.41

(1.08)

2.27ab±1.03

(1.47)

3.40ab±0.98

(1.83)

4.00cd±1.30

(1.97)

5.13bc±1.30

(2.25)

5.27b±1.53

(2.27)

3.53b±0.84

(1.81)

LGG-450 1.47a±0.74

(1.18)

2.07ab±1.03

(1.40)

3.27ab±1.10

(1.79)

3.60ab±1.18

(1.87)

4.73bc±1.38

(2.15)

5.47b±1.18

(2.33)

3.42b±0.77

(1.78)

LGG-460 1.40a±0.63

(1.16)

2.13ab±0.91

(1.43)

3.27ab±1.03

(1.76)

3.93bcd±1.03

(1.97)

5.20bc±0.94

(2.27)

4.93b±1.38

(2.20)

3.52b±0.75

(1.80)

Grand Mean 1.43±0.67

(1.17)

2.44±1.14

(1.52)

3.59±1.26

(1.87)

4.09±1.39

(1.99)

4.95±1.60

(2.19)

5.19±1.64

(2.25)

3.61±1.01

(1.83)

Values in parenthesis are square root transformed values

Values having the same alphabet are not significantly different as per DMRT.

Table 4.12. Percentage infestation of M.vitrata in different genotypes of greengram

DAS

Genotypes

Total no. of

plants 57 DAS 64 DAS 71 DAS 78 DAS 85 DAS 92 DAS Mean

WGG-42 17.33a±1.15

(4.28)

28.94ab±2.00

(32.55)

42.36b±3.02

(40.62)

42.36bc±3.02

(40.62)

42.36ab±3.02

(40.62)

42.36a±3.02

(40.62)

44.21a±0.40

(41.70)

40.43ab±2.13

(39.46)

LGG-407 20.00ab±1.00

(4.58)

30.05b±1.50

(33.25)

31.72ab±3.21

(34.28)

38.48abc±4.57

(38.34)

41.73ab±3.46

(40.25)

43.40a±6.05

(41.21)

48.50a±5.05

(44.16)

38.97a±3.57

(38.58)

PM-115 20.00ab±1.00

(4.58)

28.30ab±1.85

(32.14)

31.56ab±6.54

(34.12)

38.23abc±4.10

(38.20)

39.90ab±3.01

(39.19)

44.91a±2.75

(42.10)

48.24a±6.47

(44.01)

38.52a±2.65

(38.29)

MGG-360 20.33b±1.15

(4.62)

24.64a±1.44

(29.77)

41.19b±5.35

(39.93)

45.95c±2.68

(42.70)

47.54b±4.76

(43.61)

57.39b±4.78

(49.29)

64.08b±6.06

(53.24)

46.79b±3.43

(43.09)

PM-110 18.00ab±1.00

(4.36)

31.53b±1.68

(34.17)

35.88ab±9.73

(36.68)

39.21abc±4.38

(38.77)

39.21ab±4.38

(38.77)

46.48a±3.06

(43.00)

46.48a±3.06

(43.00)

39.79ab±3.95

(39.07)

LGG-410 19.33ab±0.57

(4.51)

29.05ab±4.83

(32.58)

37.49ab±8.30

(37.69)

40.93abc±6.58

(39.76)

42.51ab±3.83

(40.71)

47.62a±4.12

(43.65)

51.06a±4.07

(45.63)

41.44ab±4.96

(40.00)

PM-112 20.67b±2.51

(4.65)

27.84ab±1.54

(31.85)

31.44ab±1.96

(34.12)

35.25ab±3.65

(36.42)

35.25a±3.65

(36.42)

42.78a±5.30

(40.85)

46.50a±5.70

(43.01)

36.51a±2.75

(37.11)

TM-962 19.33ab±1.15

(4.51)

27.54ab±2.12

(31.66)

27.63a±3.48

(31.70)

32.81a±3.58

(34.94)

36.32a±6.07

(37.03)

44.91a±4.25

(42.09)

51.84a±6.48

(46.08)

36.84a±3.16

(37.25)

LGG-450 20.67b±2.51

(4.65)

29.33ab±3.68

(32.78)

30.92ab±4.18

(33.76)

34.36ab±7.17

(35.82)

37.80a±10.17

(37.83)

42.55a±7.61

(40.70)

50.74a±9.22

(45.46)

37.61a±6.63

(37.72)

LGG-460 19.33ab±1.15

(4.51)

31.11b±1.92

(33.91)

36.48ab±7.33

(37.12)

39.81abc±4.72

(39.12)

39.63ab±0.64

(39.03)

41.48a±2.56

(40.11)

48.52a±6.09

(44.17)

39.50ab±3.57

(38.91)

Grand

Mean

19.27±1.59

(4.50)

28.83±2.80

(32.47)

34.67±6.70

(36.00)

38.74±5.41

(38.47)

40.23±5.31

(39.35)

45.39±5.89

(42.36)

50.02±7.09

(45.05)

39.64±4.30

(38.95)

Values in parenthesis are arc sine transformed values

Values having the same alphabet are not significantly different as per DMRT.

Table 4.4. Number of webbings of M.vitrata larva per plant in different genotypes of blackgram

DAS

Genotypes

57 DAS 64 DAS 71 DAS 78 DAS 85 DAS 92 DAS Mean

LBG-709 1.40a ± 0.74

(1.53)

1.80ab ± 0.94

(1.65)

2.00ab ± 0.93

(1.38)

2.87b± 0.99

(1.67)

3.73b ± 1.34

(1.90)

4.40b± 1.35

(2.07)

2.70b ± 0.79

(1.70)

PU-31 1.60a ± 0.74

(1.60)

1.73ab± 0.96

(1.63)

2.60b ± 1.06

(1.58)

2.87b ± 0.99

(1.67)

3.87b± 1.06

(1.95)

5.00b± 1.00

(2.22)

2.95b ± 0.76

(1.78)

LBG-20 1.20a±0.56

(1.47)

1.67ab±0.90

(1.61)

2.13ab±0.83

(1.43)

3.47b±1.25

(1.83)

4.00b±1.65

(1.95)

5.07b±1.67

(2.22)

2.92b±0.81

(1.75)

LBG-790 1.33a±0.62

(1.52)

2.93c±0.96

(1.97)

3.73c±1.34

(1.90)

5.07c±1.62

(2.22)

6.80c±1.37

(2.6)

7.67c±1.95

(2.74)

4.60c±1.00

(2.16)

LBG-752 1.47a±0.74

(1.56)

1.60ab±0.63

(1.60)

2.53ab±0.83

(1.57)

3.60b ±1.40

(1.85)

4.73b ±1.34

(2.16)

5.40b±1.35

(2.31)

3.20b±0.78

(1.84)

LBG-792 1.27a±0.59

(1.50)

1.33a±0.49

(1.52)

2.20ab±0.86

(1.46)

3.00b±1.07

(1.70)

4.00b±1.36

(1.97)

5.07b±1.34

(2.23)

2.81b±0.6

(1.73)

LBG-123 1.60a± 0.74

(1.60)

2.20b±1.01

(1.77)

2.73b±1.03

(1.63)

3.53b ±1.06

(1.86)

4.40b±0.91

(2.09)

5.33b±0.9

(2.30)

3.30b±0.54

(1.87)

LBG-791 1.40a±0.63

(1.54)

1.73ab ±0.70

(1.64)

2.20ab±0.86

(1.46)

2.93b±0.88

(1.69)

4.07b±1.22

(1.99)

4.67b±0.98

(2.15)

2.83b±0.62

(1.74)

LBG-645 1.33a±0.49

(1.52)

1.40a±0.63

(1.54)

1.73a±0.96

(1.27)

1.73a±0.80

(1.29)

2.60a±0.99

(1.59)

3.33a±0.98

(1.81)

2.02a±0.50

(1.50)

Grand Mean 1.40 ± 0.65

(1.54)

1.82 ± 0.92

(1.66)

2.43 ± 1.09

(1.52)

3.22 ± 1.39

(1.75)

4.24 ± 1.62

(2.02)

5.10 ± 1.68

(2.23)

3.04 ± 0.96

(1.79)

Values in parenthesis are square root transformed values

Values having the same alphabet are not significantly different as per DMRT.

Table 4.5. Total number of M.vitrata caterpillars per plant in different genotypes of blackgram

DAS

Genotypes

57 DAS 64 DAS 71 DAS 78 DAS 85 DAS 92 DAS Mean

LBG-709 0.80a±0.86

(1.31)

0.80a±0.68

(1.32)

1.87a±1.30

(1.64)

4.33b±1.72

(2.27)

3.87b±1.81

(2.17)

3.27b±1.58

(1.75)

2.48b±0.66

(1.74)

PU-31 1.07a±0.80

(1.41)

1.27a±1.53

(1.44)

3.20bc±1.15

(2.03)

3.93b±1.53

(2.20)

3.93b±1.58

(2.19)

3.07b±1.22

(1.72)

2.74bc±0.78

(1.83)

LBG-20 0.73a±0.59

(1.30)

0.93a±0.59

(1.37)

2.87abc±1.51

(1.92)

4.07b±2.22

(2.19)

4.40b±1.81

(2.29)

3.40b±1.60

(1.79)

2.73bc±0.82

(1.81)

LBG-790 1.00a±0.93

(1.38)

1.20a±0.68

(1.46)

3.73c±1.71

(2.14)

6.80c±1.61

(2.78)

7.00c±1.20

(2.82)

4.73c±1.71

(2.14)

4.07d±0.74

(2.12)

LBG-752 1.13a±1.19

(1.41)

0.87a±0.52

(1.35)

3.07bc±1.03

(2.00)

4.80b±2.01

(2.37)

5.87c±1.46

(2.61)

3.07b±1.71

(1.69)

3.13c±0.70

(1.91)

LBG-792 0.87a±0.74

(1.34)

0.73a±0.46

(1.30)

2.40ab±1.30

(1.81)

4.33b±1.68

(2.28)

4.67b±2.02

(2.33)

3.20b±1.61

(1.74)

2.70bc±0.56

(1.80)

LBG-123 0.67a±0.72

(1.26)

0.93a±0.59

(1.37)

3.60c±1.55

(2.12)

4.33b±1.76

(2.28)

3.87b±1.73

(2.17)

2.87b±1.06

(1.67)

2.71bc±0.71

(1.81)

LBG-791 1.00a±0.85

(1.39)

0.67a±0.49

(1.28)

3.20bc±1.27

(2.03)

3.93b±1.75

(2.19)

4.47b±1.30

(2.32)

2.93b±1.34

(1.67)

2.70bc±0.62

(1.81)

LBG-645 0.80a±0.68

(1.32)

0.73a±0.70

(1.29)

2.27ab±1.10

(1.78)

2.27a±1.49

(1.76)

2.07a±1.44

(1.70)

1.60a±0.99

(1.19)

1.62a±0.59

(1.51)

Grand

Mean

0.89 ± 0.82

(1.35)

0.90 ± 0.76

(1.35)

2.91 ± 1.42

(1.94)

4.31 ± 2.04

(2.26)

4.46 ± 2.04

(2.29)

3.12 ± 1.59

(1.19)

2.76 ± 0.90

(1.82)

Values in parenthesis are square root transformed values

Values having the same alphabet are not significantly different as per DMRT.

Table 4.6. Percentage infestation of M.vitrata in differen genotypes of blackgram

DAS

Genotypes

Total no. of

plants 57 DAS 64 DAS 71 DAS 78 DAS 85 DAS 92 DAS Mean

LBG-709 19.00a±1.00

(4.36)

35.06b±1.75

(36.32)

31.63a±1.66

(34.24)

37.00a±6.66

(37.44)

42.46ab±11.37

(40.63)

45.88bc±8.43

(42.65)

54.67bc±10.46

(47.46)

41.11bc±6.08

(39.84)

PU-31 20.67ab±1.52

(4.54)

30.48ab±3.69

(33.5)

29.38a±7.09

(32.73)

30.89a±5.19

(33.74)

35.75ab±5.55

(36.70)

40.60ab±5.91

(39.58)

45.29ab±3.80

(42.31)

35.39ab±3.85

(36.43)

LBG-20 19.67ab±1.52

(4.43)

25.60a±5.79

(30.31)

27.11a±1.87

(31.39)

30.63a±2.44

(33.61)

37.32ab±2.05

(37.67)

40.76ab±5.05

(39.68)

45.95ab±3.66

(42.69)

34.56ab±2.13

(35.89)

LBG-790 19.67ab±1.52

(4.43)

30.63ab±2.44

(33.61)

35.92a±7.56

(36.78)

37.59a±5.99

(37.80)

44.28b±5.15

(41.73)

54.50c±5.85

(47.62)

64.71c±6.57

(53.64)

44.60c±5.50

(41.86)

LBG-752 19.67ab±1.52

(4.43)

25.52a±2.03

(30.35)

35.47a±2.41

(36.57)

37.32a±2.05

(37.67)

38.99ab±0.96

(38.66)

46.03bc±6.87

(42.72)

51.21b±11.58

(45.71)

39.09abc±2.93

(38.61)

LBG-792 20.33ab±0.57

(4.51)

27.86a±2.57

(31.86)

29.36a±7.55

(32.72)

32.70a±4.67

(34.86)

32.86a±3.71

(34.97)

39.36ab±5.12

(38.86)

49.20ab±5.18

(44.57)

35.22ab±1.67

(36.30)

LBG-123 20.00ab±1.00

(4.47)

29.97ab±4.39

(33.17)

33.56a±7.43

(35.34)

33.56a±7.43

(35.34)

38.40ab±3.56

(38.30)

43.32ab±1.50

(41.18)

51.67b±1.45

(45.98)

38.41abc±3.27

(38.22)

LBG-791 22.00b±2.00

(4.69)

25.76a±1.31

(30.51)

30.32a±1.35

(33.43)

31.84a±3.93

(34.34)

33.51a±3.80

(35.36)

36.69ab±6.53

(37.24)

44.32ab±6.32

(41.74)

33.73a±3.42

(35.44)

LBG-645 20.33ab±0.57

(4.51)

31.19ab±3.37

(33.95)

31.11a±5.35

(33.86)

32.78a±2.54

(34.93)

32.78a±2.54

(34.93)

34.44a±0.96

(35.95)

37.70a±2.52

(37.89)

33.33a±0.83

(35.25)

Grand Mean 20.15 ± 1.38

(4.49)

29.12 ± 4.14

(32.62)

31.54 ±5.31

(34.12)

33.81 ±4.88

(35.53)

37.37 ± 5.84

(37.66)

42.40 ± 7.39

(40.61)

49.41 ± 9.13

(44.70)

37.28 ± 4.77

(37.54)

Values in parenthesis are arc sine transformed values; Values having the same alphabet are not significantly different as per DMRT

Table 4.13. Larval preference of Maruca vitrata on different

genotypes of blackgram in free choice experiment

Genotypes No. of larvae after 24 hrs

LBG-645 (Resistant) 1.57a ± 0.53

(1.24)

LBG-791 (Moderate resistant) 1.86ab ± 0.69

(1.34)

LBG-790 (Susceptible) 2.57b ± 0.97

(1.57)

Total mean 2.00 ± 0.83

(1.38)

LSD 0.77 *Values in parenthesis are square root transformed

*Values having the same alphabet are not significantly different

Table 4.15. Larval preference of Maruca vitrata on different genotypes

of greengram in free choice experiment

Genotypes No. of larvae after 24 hrs

WGG-42 (Resistant) 1.43a ± 0.53

(1.18)

TM-962 (Moderate resistant) 1.71a ± 0.75

(1.28)

MGG-360 (Susceptible) 2.57b ± 0.83

(1.58)

Total mean 1.90 ± 0.83

(1.34)

LSD 0.77

*Values in parenthesis are square root transformed

*Values having the same alphabet are not significantly different

Table 4.14. Biology of M.vitrata in resistant, moderate resistant and susceptible genotypes of blackgram in no choice technique

Genotype

2nd instar

larva

duration

(days)

3rd instar

larva

duration

(days)

4th instar

larva

duration

(days)

5th

instar larva

duration

(days)

Larval

duration

(days)

3rd instar larval

weight (gms)

4th instar larval

weight (gms)

Pupal weight

(gms)

Pupal

duration

(days)

Adult

longevity

(days)

LBG-645

(Resistant) 3.43a ±0.54 3.57a ±0.54 3.00 b± 0.54 3.00ab ± 0.54 13.00 a± 0.54 0.0325a ± 0.0019 0.0449a ± 0.0021 0.0398a ± 0.0021 5.57c ± 0.54 6.45c ± 0.59

LBG-791

(Moderate

resistant)

3.29a ±0.54 3.29a ±0.54 2.57ab ± 0.54 3.57b ± 0.54 12.71a ± 0.54 0.0362b ± 0.0022 0.0483a ± 0.0013 0.0422a ± 0.0021 5.21b ± 0.47 5.79b ± 0.64

LBG-790

(Susceptible) 3.43a ±0.54 3.14a ±0.54 2.43a ± 0.54 2.86a ± 0.54 11.86a ± 0.54 0.0418c ± 0.0058 0.0556b ± 0.0053 0.0447a ± 0.0033 4.52a ± 0.5 4.98a ± 0.56

Grand mean 3.38 ±0.54 3.33 ±0.54 2.67 ± 0.54 3.14 ± 0.54 12.52 ± 0.54 0.0369 ± 0.0053 0.0496 ± 0.0056 0.0422 ± 0.0032 5.1 ± 0.67 5.74 ± 0.85

LSD 0.58 0.52 0.49 0.68 1.25 0.0042 0.0042 0.0042 0.11 0.22

*Values having the same alphabet are not significantly different

Table 4.16. Biology of M.vitrata in resistant, moderate resistant and susceptible genotypes of greengram in no choice technique

Genotype

2nd instar

larva

duration

(days)

3rd

instar larva

duration

(days)

4th

instar

larva

duration

(days)

5th

instar larva

duration

(days)

Larval

duration

(days)

3rd instar larval

weight (gms)

4th instar larval

weight (gms)

Pupal weight

(gms)

Pupal

duration

(days)

Adult

longevity

(days)

WGG-42

(Resistant) 3.14a ± 0.38 3.71a ± 0.49 2.86b ±0.38 3.71b ± 0.49 13.43b ± 0.53 0.0342a ± 0.0018 0.0444a ± 0.0026 0.0397a ± 0.0020 5.55c± 0.55 6.45c ± 0.6

TM-962

(Moderate

resistant)

3.57b± 0.53 3.29a ± 0.49 2.71b ±0.49 3.43b ± 0.53 13.00b ± 1.15 0.0380b ± 0.0035 0.0459a ± 0.0031 0.0425b ± 0.0019 5.21b ± 0.47 5.79b± 0.64

MGG-360

(Susceptible) 3.00a± 0.00 3.43a ± 0.53 2.14a ± 0.38 2.57a ± 0.53 11.14a ± 1.21 0.0440c ± 0.0021 0.0525b ± 0.0016 0.0468c ± 0.0012 4.52a± 0.5 5.21a± 0.52

Grand mean 3.24 ± 0.44 3.48 ± 0.51 2.57 ± 0.51 3.24 ± 0.7 12.52 ± 1.4 0.0387 ± 0.0048 0.0476 ± 0.0043 0.0430 ± 0.0034 5.1 ± 0.66 5.82± 0.77

LSD 0.42 0.56 0.47 0.58 1.14 0.002 0.002 0.002 0.12 0.21

*Values having the same alphabet are not significantly different

Table 4.19. Correlation study of M.vitrata growth parameters and blackgram characters (physical and

biochemical)

Insect growth parameters Correlation Trichome

density

Chlorophyll

(SCMR)

Phenols

(mg/g)

Proteins

(mg/g)

Reducing

Sugars

(mg/g)

Number of insect larvae in each

treatment after 24 hrs

Pearson

Correlation -0.049 0.344 -.537* 0.389 .486*

2nd instar larval duration Pearson

Correlation 0.15 0.092 0.00 0.159 0.074

3rd instar larval duration Pearson

Correlation 0.261 -0.353 0.255 -0.406 -0.257

4th instar larval duration Pearson

Correlation 0.339 -.502* .522* -0.279 -0.42

5th instar larval duration Pearson

Correlation -0.173 -0.092 -0.019 0.067 -0.245

Larval duration Pearson

Correlation 0.215 -0.366 0.311 -0.178 -0.386

3rd instar larval weight Pearson

Correlation -0.167 0.556** -0.667** 0.691** 0.693**

4th instar larval weight Pearson

Correlation -0.056 0.629** -0.733** 0.812** 0.809**

Pupal weight Pearson

Correlation -0.096 0.545* -0.665** 0.767** 0.744**

Pupal duration Pearson

Correlation 0.088 -0.721** 0.904** -0.892** -0.959**

Adult longivity Pearson

Correlation 0.142 -0.811** 0.900** -0.885** -0.906**

** Correlation is significant at the 0.01 level (2-tailed) *Correlation is significant at the 0.05 level (2-tailed)

Table 4.23. Correlation study of M.vitrata growth parameters and greengram characters (physical and

biochemical)

Insect growth parameters Correlation

Trichome

density

Chlorophyll

(SCMR)

Phenols

(mg/g)

Proteins

(mg/g)

Reducing

Sugars

(mg/g)

Number of insect larvae in each

treatment after 24 hrs

Pearson

Correlation -0.187 -0.016 -0.486* 0.479* 0.525*

2 nd instar larval duration Pearson

Correlation -0.776** -0.334 0.213 -0.298 -0.216

3 rd instar larval duration Pearson

Correlation 0.418 0.294 0.148 -0.14 -0.217

4 th instar larval duration Pearson

Correlation 0.041 -0.046 0.581** -0.624** -0.599**

5 th instar larval duration Pearson

Correlation 0.027 -0.022 0.669** -0.734** -0.733**

Larval duration Pearson

Correlation -0.061 -0.024 0.666** -0.737** -0.730**

3 rd instar larval weight Pearson

Correlation -0.072 -0.1 -0.783** 0.848** 0.857**

4 th instar larval weight Pearson

Correlation 0.052 0.071 -0.735** 0.821** 0.838**

Pupal weight Pearson

Correlation -0.181 -0.191 -0.884** 0.920** 0.935**

Pupal duration Pearson

Correlation 0.034 0.12 0.936** -0.961** -0.966**

Adult longivity Pearson

Correlation 0.07 0.31 0.898** -0.891** -0.897**

** Correlation is significant at the 0.01 level (2-tailed) *Correlation is significant at the 0.05 level (2-tailed

Table 4.20. Regression study of M.vitrata growth parameters and blackgram characters (physical and biochemical)

S. No Insect growth

parameters Regression equation

R2

values

1 Number of larvae

after 24 hrs.

y= 30.360 +0.000(trichome density) -0.010(chlorophyll) - 0.258(phenols) - 0.079(proteins) +

0.043(reducing sugars) 0.351

2 4th instar larval

duration

y= -61.509 + 0.489(trichome density)-0.02(chlorophyll) + 0.27(phenols) + 0.311(proteins) –

0.123(reducing sugars) 0.347

3 3rd instar

larvalweight

y= 0.004-0.002(trichome density)- 0.0000403(chlorophyll)-0.001(phenols) + 0.001(proteins)

+ 0.001(reducing sugars) 0.530

4 4th instar larval

weight

y= -0.15 + 0.001(trichome density)-0.00000421(chlorophyll)-0.001(phenols) + 0.002

(proteins) + 0.001(reducing sugars) 0.701

5 Pupal weight y= -0.088 + 0.00(trichome density)-0.000048(chlorophyll) + 0.0001(phenols) + 0.001

(proteins) + 0.0001(reducing sugars) 0.613

6 Pupal duration y= -6.1 + 0.005(trichome density) + 0.007(chlorophyll) + 0.231(phenols)-0.016(proteins)-

0.1(reducing sugars) 0.966

7 Adult longevity y= 0.721-0.019(trichome density)- 0.018(chlorophyll)-0.245(phenols)-0.058(proteins) –

0.086(reducing sugars) 0.886

Table 4.24. Regression study of M.vitrata growth parameters and greengram characters (physical and biochemical)

S. No Insect growth

parameters Regression equation R2 values

1 Number of larvae after

24 hrs

y= 13.265-0.186(trichome density) + 0.014(chlorophyll)-0.04(phenols) -

0.09(proteins) + 0.191(reducing sugars) 0.360

2 2nd instar laarval

duration

y= 11.281-0.759(trichome density) + 0.017(chlorophyll) + 0.259

(phenols)-0.179(proteins) + 0.205(reducing sugars) 0.718

3 4th instar larval duration y= 34.416 + 0.285(trichome density) - 0.026(chlorophyll) + 0.3(phenols)-

0.402(proteins) + 0.254(reducing sugars) 0.445

4 5th instar larval duration y= 67.286 + 0.257(trichome density)-0.021(chlorophyll) - 0.201(phenols)-

0.305(proteins)-0.199(reducing sugars) 0.572

5 Larval duration y= 151.019+0.085(trichome density)-0.015(chlorophyll)- 0.551(phenols)-

0.586(proteins)- 0.466(reducing sugars) 0.556

6 3rd instar larval weight y=-0.55-0.001(trichome density)-0.0000115(chlorophyll) + 0.004(phenols)

+ 0.002(proteins) + 0.003(reducing sugars) 0.761

7 4th instar larval weight y=-0.372-0.001(trichome density)- 0.0000957(chlorophyll) + 0.004

(phenols)+ 0.0001(proteins) + 0.004(reducing sugars) 0.748

8 Pupal weight y=-0.275-0.001(trichome density)- 0.00000183(chlorophyll) + 0.001

(phenols)+0.001(proteins) + 0.001(reducing sugars) 0.920

9 Pupal duration y= 22.968+ 0.059(trichome density)-0.002(chlorophyll) + 0.138(phenols)-

0.162(proteins)-0.129(reducing sugars) 0.947

10 Adult longivity y=29.595-0.109(trichome density) + 0.028(chlorophyll) + 0.129(phenols)-

0.198(proteins)-0.129(reducing sugars) 0.877

Table 4.25. Tolerance of larvae of Maruca to chlorpyriphos on resistant and susceptible

genotypes of blackgram

Table 4.26. Tolerance of larvae of Maruca to chlorpyriphos on resistant and susceptible

genotypes of greengram

Genotypes LC 50

(µL/ml)

Lower Fiducial

limits

Higher Fiducial

limits

LD50

(µg/g)

WGG-42

(Resistant) 1.39 1.05 1.78 36.98

MGG-360

(Susceptible) 1.63 1.07 1.85 36.85

LSD 0.07 - - 2.32

Genotypes LC 50

(µL/ml)

Lower

Fiducial limits

Higher Fiducial

limits

LD50

(µg/g)

LBG-645 (Resistant) 1.06 0.68 1.70 29.39

LBG-790 (Susceptible) 1.57 0.86 1.88 35.72

LSD 0.31 - - 6.39

Table 4.17. Physical characters of resistant, moderate resistant and susceptible genotypes of blackgram

*Values in parenthesis are square root transformed *Values having the same alphabet are not significantly different

Table 4.18. Biochemical characters of resistant, moderate resistant and susceptible genotypes of blackgram

Genotypes Phenols (mg/g) Proteins (mg/g) Reducing sugars (mg/g)

LBG-645

(Resistant) 70.37c ± 0.21 148.52a ± 0.46 25.20a ± 0.35

LBG-791

(Moderate Resistant) 69.27b ± 0.26 149.97b ± 0.72 26.31b ± 0.38

LBG-790

(Susceptible) 68.55a ± 0.38 151.92c ± 0.73 31.71c ± 0.37

Mean 69.40 ± 0.81 150.14 ± 1.55 27.74 ± 2.94

LSD 0.32 0.73 0.41

*Values having the same alphabet are not significantly different

Genotypes Trichome

density

Leaf area

(cm2)

Leaf dry

weight (gm)

Leaf toughness

(cm2/gm)

Chlorophyll

(SCMR)

Plant height

(cm)

LBG-645

(Resistant)

41.57a ± 4.04

(6.44) 159.71 a ± 3.55 0.76 a ± 0.03 210.88 a ± 4.03 36.4 a ± 4.87 35.36 a ± 1.64

LBG-791

(Moderate Resistant)

37.43 a ± 4.28

(6.11) 159.43 a ± 4.50 0.74 a ± 0.04 214.43 a ± 5.53 44.9 b ± 2.26 35.1 a ± 2.03

LBG-790

(Susceptible)

39.71 a ± 2.63

(6.3) 156.29 a ± 4.75 0.73 a ± 0.04 215.65 a ± 6.24 48.75b ± 3.15 34.88 a ± 1.84

Mean 39.57 ± 3.93

(6.28) 158.48 ± 4.37 0.74 ± 0.04 213.65 ± 5.48 43.35 ± 6.3 35.11 ± 1.76

LSD 4.18

4.83 0.04 5.99 4.04 2.06

Table 4.21. Physical characters of resistant, moderate resistant and susceptible genotypes of greengram

Genotypes Trichome

density Leaf area (cm2)

Leaf dry weight

(gm)

Leaf toughness

(cm2/gm)

Chlorophyll

(SCMR)

Plant height

(cm)

WGG-42

(Resistant)

55.29b ± 6.75

(7.42) 186.57a ± 4.65 1.22a ± 0.03 152.21a ± 1.2 50.67b ± 4.47 43.66 a ± 0.67

TM-962

(Moderate Resistant)

44.86a ± 6.18

(6.68) 188.86a ± 7.22 1.25a ± 0.04 150.25a ± 3.55 39.80a ± 3.44 45.91b ± 0.72

MGG-360

(Susceptible)

52.71b ± 5.25

(7.25) 190.29a ± 6.37 1.25a ± 0.04 151.87a ± 1.29 46.91b ± 3.41 43.20a ± 1.87

Mean 50.95 ± 7.35

(7.12) 188.57 ± 6.06 1.24 ± 0.04 151.44 ± 2.34 45.79 ± 5.86 44.26 ± 1.68

LSD 6.84 6.93 0.04 2.56 4.27 1.37

*Values in parenthesis are square root transformed *Values having the same alphabet are not significantly different

Table 4.22. Biochemical characters of resistant, moderate resistant and susceptible genotypes of greengram

Genotypes Phenols (mg/g) Proteins (mg/g) Reducing sugars (mg/g)

WGG-42

(Resistant) 69.74c ± 0.12 148.61a ± 0.25 25.37a ± 0.19

TM-962

(Moderate Resistant) 69.23b ± 0.12 149.35b ± 0.23 26.32b ± 0.20

MGG-360

(Susceptible) 68.50a ± 0.22 151.46c ± 0.13 28.36c ± 0.18

Mean 69.16 ± 0.54 149.81 ± 1.25 26.68 ± 1.28

LSD 0.18 0.24 0.22

*Values having the same alphabet are not significantly different