Influence of leaf surfaces and spray droplets on the ...psasir.upm.edu.my/12354/1/FP_2010_4A.pdf · morfologi permukaan daun, maka kekasaran permukaan daun dan lilin epicutikular

UNIVERSITI PUTRA MALAYSIA

EFFECTS OF LEAF SURFACE CHARACTERISTICS AND SPRAY DROPLETS ON EFFECTIVENESS OF SELECTED GLYPHOSATE

FORMULATIONS

NORHAYATI BINTI NGAH FP 2010 4

i

EFFECTS OF LEAF SURFACE CHARACTERISTICS AND SPRAY DROPLETS

ON EFFECTIVENESS OF SELECTED GLYPHOSATE FORMULATIONS

By

NORHAYATI BINTI NGAH

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia, in

Fulfilment of the Requirements for the Degree of Master of Science

February 2010

ii

Dedicated to:

My belated mother

(Sulong binti Mohd Noor)

For her true love, support and inspiration

iii

Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of

the requirements for the degree of Master of Science

EFFECTS OF LEAF SURFACE CHARACTERISTICS AND SPRAY DROPLETS

ON EFFECTIVENESS OF SELECTED GLYPHOSATE FORMULATIONS

By

NORHAYATI NGAH

February 2010

Chairman : Dzolkhifli Omar, PhD.

Faculty : Agriculture

Laboratory and glasshouse studies were conducted to examine the effect of leaf surfaces

and spray droplets on the effectiveness of glyphosate on some selected plants. The broad

leaves plants selected were Diodia ocimifolia, Borreria latifolia, Clidemia hirta, Cleome

rutidosperma, Mikania micrantha and Asystasia gangetica, while the narrow leaves

consisted of Eleusine indica, Imperata cylindrica, Cyperus kylingia, Axonopus

compressus, Pennisetum polistachyon and Paspalum conjugatum. The deposition of

pesticide depends on the morphology of leaf surface, thus the leaf surface roughness and

epicuticular wax were evaluated. The plants were categorized accordingly to the different

type of roughness based on the estimation of three roughness parameters Ra (arithmetic

average height parameter), Rq (root-mean-square roughness parameter corresponding to

Ra), and Rz (average of high peaks and low valleys over the evaluation length). The leaf

was examined by using scanning electron microscopy for the surface roughness while the

epicuticular wax content of the leaf was extracted by using chloroform. The amount of

iv

wax extracted from the plants varied between species. For broad leaves plant, M.

micrantha (44.22µgcm-2

) contained the highest quantity of wax. Clidemia hirta

(24.03µgcm-2

) and A. gangetica (23.03µgcm-2)

were grouped in the plant with medium

quantity of wax while C. rutidosperma (16.52µgcm-2

), B. latifolia (14.19µgcm-2

) and D.

ocimifolia (10.75µgcm-2

) were grouped in plant with low quantity of cuticular wax

weight. For narrow leaves plant, E. indica (44.23µgcm-2

) and I. cylindrica (49.88µgcm-2

)

have the highest quantity of wax. Pennisetum polystachion (32.16µgcm-2

) and C.

kylingia (22.85µgcm-2

) were categorized under the plant with medium quantity of wax

whereas P. conjugatum (19.59µgcm-2

) and A. compressus (16.78µgcm-2

) were

categorized with low quantity of wax. The wax on the abaxial and adaxial leaf surface of

the broad leaves plants was found to be significantly different. In contrast, the amount of

wax on the abaxial and adaxial leaf surface of the narrow leaves plants was more or less

similar. For the leaf surface roughness of the broad leaves species, B. latifolia were

categorized as the roughest followed by C. hirta, D. ocimifolia, A. gangetica, and C.

rutidosperma. Mikania micrantha had the smoothest leaf surface among the broad leaves

species. On the other hand, the narrow leaves of P. polistachyon were identified as the

roughest followed by I. cylindrica and P. conjugatum while E. indica, A. compressus and

C. kylingia were categorized in the smoothest surface.

The effect of leaf surface roughness and epicuticular wax on the spread area of spray

droplets of glyphosate was studied by measuring the spread area of 1μL, 2μL and 3μL of

micro-emulsion formulation (ME4), soluble solution formulation (AS2), Roundup® and

water on the adaxial leaf surfaces of each of the plant species. The spread area of all

formulations and volume of droplets varied between species. The spread area showed

v

that the amount of wax on leaf surface played important role as compared to the leaf

surface roughness. Nevertheless, the leaf surface roughness to some extends influence

for the spread droplets. ME4 gave twice spread diameter area of the droplet than AS2

and Roundup®. The ratio of spread droplet showed the smaller the droplet volume, the

better the spread was obtained. The ratio of spread area of 1μL, 2μL and 3μL droplet of

all formulations was estimated at about 2, 3 and 4 respectively.

The efficacy of the formulations was then evaluated in the glasshouse by spraying the

plants using 3 different nozzles to represent the small (250 microns), medium (350

microns) and coarse (450 microns) droplets. The spray deposition was recorded 1 hour

after the application. The chlorophyll degradation was determined on the first, third,

seventh and fourteenth day and mortality of weeds was recorded third, seventh, tenth and

fourteenth day after spraying. Ten days after spraying, the base of plant was cut and the

fresh weights of each species were recorded. Results of all those parameters varied

among the species. In general, smaller droplet size, will give better deposition. The

droplet size and the leaf surface characteristic were confirmed affecting the amount of

spray deposition. The solution sprayed with smaller droplets size was more effective than

the coarse droplet size in killing the plants for most of plant species. However, the coarse

droplet spray was found to be better in controlling the plants with hairy surface as

compared to fine droplet. The micro emulsion formulation (ME4) was found to give

better efficacy in killing the plants than the water soluble formulation (AS2) and

Roundup®.

vi

Abstrak tesis ini dikemukakan kepada Senat Universiti Putra Malaysia sebagai

memenuhi keperluan untuk Ijazah Master Sains

KESAN CIRI PERMUKAAN DAUN DAN TITIK SEMBURAN KE ATAS

KEBERKESANAN FORMULASI GLYPHOSATE TERPILIH

Oleh

NORHAYATI NGAH

Februari 2010

Pengerusi : Dzolkhifli Omar, PhD.

Fakulti : Pertanian

Kajian makmal dan rumah kaca telah dilaksanakan bertujuan untuk mengkaji kesan

permukaan daun dan titik semburan ke atas keberkesanan glifosat terhadap beberapa

tumbuhan terpilih. Tumbuhan daun lebar yang dipilih adalah Diodia ocimifolia, Borreria

latifolia, Clidemia hirta, Cleome rutidosperma, Mikania micrantha dan Asystasia

gangetica, manakala tumbuhan daun tirus merangkumi Eleusine indica, Imperata

cylindrica, Cyperus kylingia, Axonopus compressus, Pennisetum polistachyon dan

Paspalum conjugatum. Lantaran mendapan racun perosak turut bergantung kepada

morfologi permukaan daun, maka kekasaran permukaan daun dan lilin epicutikular juga

dinilai. Tumbuhan dikategorikan berdasarkan kepada anggaran tiga parameter kekasaran

iaitu Ra (parameter purata ketinggian aritmetik), Rq (punca kuasa dua nilai parameter

kekasaran Ra), dan Rz (purata tinggi dan rendah puncak lembah ke atas nilai panjang).

Daun diperiksa dengan menggunakan mikroskop elektron untuk menilai kekasaran

permukaan sementara lilin epicuticular daun diekstrak dengan menggunakan kloroform.

vii

Kandungan lilin yang diekstrak daripada daun tumbuhan adalah bervariasi antara spesies.

Untuk tumbuhan daun lebar, M. micrantha (44.22 µgcm-2

) dikenalpasti sebagai

tumbuhan yang mengandungi jumlah lilin tertinggi. Clidemia Hirta (24.03 µgcm-2

) dan

A. gangetica (23.03 µgcm-2

) dikategorikan sebagai tumbuhan dengan kuantiti lilin yang

sederhana, sementara C. rutidosperma (16.52 µgcm-2

), B. latifolia (14.19 µgcm-2

) dan D.

ocimifolia (10.75 µgcm-2

) dikategorikan sebagai tumbuhan dengan kuantiti lilin

epikuticular yang rendah. Untuk tumbuhan daun tirus, E. indica (44.23 µgcm-2

) dan I.

cylindrica (49.88 µgcm-2

) diakui mempunyai jumlah lilin terbanyak. Pennisetum

polystachion (32.16 µgcm-2

) dan C. kylingia (22.85 µgcm-2

) dikategorikan sebagai

tumbuhan yang mempunyai jumlah lilin sederhana manakala P. conjugatum (19.59

µgcm-2

) dan A. compressus (16.78 µgcm-2

) berada dalam kategori tumbuhan yang

mempunyai kuantiti lilin yang rendah. Jumlah lilin pada permukaan atas dan bawah daun

bagi tumbuhan berdaun lebar mempunyai perbezaan yang nyata. Sebaliknya, jumlah lilin

pada permukaan atas dan bawah bagi tumbuhan berdaun tirus adalah lebih kurang sama.

Untuk nilai kekasaran permukaan daun daripada tumbuhan berdaun lebar, B. latifolia

dikategorikan sebagai paling kasar diikuti oleh C. hirta, D. ocimifolia, A. gangetica, dan

C. rutidosperma. M. micrantha mempunyai permukaan daun yang paling halus di antara

spesies daun lebar. Bagi tumbuhan berdaun tirus P. polistachyon telah dikenalpasti

sebagai paling kasar diikuti oleh I. cylindrica, dan P. conjugatum sementara E. indica, A.

compressus dan C. kylingia dikategorikan sebagai mempunyai permukaan yang halus.

Kesan daripada kekasaran permukaan daun dan jumlah lilin epicuticular ke atas

penyebaran titisan semburan glifosat telah dikaji dengan mengukur luas penyebaran 1μL,

2μL dan 3μL formulasi larutan mikro (ME4), formulasi solusi larut (AS2), Roundup ®

viii

dan air pada permukaan atas daun bagi semua spesis tumbuhan. Keluasan kawasan

penyebaran oleh semua jenis formulasi dan saiz titisan adalah bervariasi di antara semua

spesis. Keluasan penyebaran menunjukkan bahawa jumlah lilin pada permukaan daun

memainkan peranan penting berbanding dengan kekasaran permukaan daun. Walau

bagaimana pun, dalam keadaan tertentu kekasaran permukaan daun boleh bertindak

sebagai faktor penentu untuk penyebaran titisan. ME4 memberikan nilai dua kali ganda

diameter luas titisan yang tersebar berbanding AS2 dan Roundup®. Nisbah penyebaran

titisan menunjukkan bahawa semakin kecil saiz titisan, semakin baik penyebaran yang

diperolehi. Nisbah luas penyebaran bagi isipadu 1μL, 2μL dan 3μL bagi semua formulasi

adalah dianggarkan sekitar 2:3:4.

Keberkesanan formulasi kemudiannya dinilai dalam rumah kaca dengan menyembur

tumbuhan menggunakan 3 jenis nozel yang berbeza untuk mewakili saiz titik semburan

sederhana (250 mikron), kasar (350 mikron) dan sangat kasar (450 mikron). Mendapan

penyemburan telah direkodkan satu jam selepas aplikasi. Kandungan klorofil daun

ditentu ukur pada hari pertama, ketiga, ketujuh dan keempat belas manakala tahap

kematian direkod pada hari ketiga, ketujuh, kesepuluh dan empat belas hari selepas

semburan. 10 hari selepas semburan, pangkal tumbuhan dipotong dan berat basah dan

berat kering tumbuhan direkod. Keputusan daripada semua parameter adalah bervariasi

di antara spesies. Secara umumnya, semakin kecil isipadu titisan, semakin tinggi nilai

endapan racun. Isipadu titisan dan ciri permukaan daun disahkan mempengaruhi jumlah

endapan semburan. Solusi semburan yang disembur dengan saiz titisan yang lebih kecil

adalah lebih berkesan berbanding saiz titisan yang besar untuk membunuh sebahagian

besar rumpai. Namun, isipadu titisan yang kasar didapati adalah lebih berkesan untuk

ix

mengawal tumbuhan yang mempunyai permukaan berbulu berbanding dengan isipadu

titisan halus. Formulasi emulsi mikro (ME4) didapati paling berkesan untuk mengawal

tumbuhan berbanding perumusan larut (AS2) dan Roundup ®.

x

ACKNOWLEDGEMENTS

In the Name of Allah, the Most Gracious, the Most Merciful…

I am grateful to the Head and members of Department of Plant Protection, Dean and

entire members of the Faculty of Agriculture and School of Graduate Studies for their

assistance during my graduate study at Universiti Putra Malaysia. I would like to express

special thank to my supervisor, Professor Dr. Dzolkhifli Omar as well as my co-

supervisor, Assoc. Professor Dr. Abdul Shukor Juraimi for their technical support,

comments, suggestions, guidance, and patience during supervising my research. In

particular, I owe my gratitude to both of them for sharing me a lot of knowledge. My

sincere gratitude is also due to all Toxicology and Plant Physiology Laboratory staffs for

helping me in this research. I wish to express my thanks to all of my friends who were

very helpful and for their tireless support to complete this thesis. I also thank my beloved

family, whose true love, support and inspiration made this work possible.

xi

I certify that an Examination Committee met on 23rd

March 2010 to conduct the final

examination of Norhayati Ngah on his Master of Science thesis entitled “Effects of Leaf

Surface Characteristics and Spray Droplets on Effectiveness of Selected Glyphosate

Formulations” in accordance with Universiti Pertanian Malaysia (Higher Degree) Act

1980 and Universiti Pertanian Malaysia (Higher Degree) Regulations 1981. The

committee recommends that the candidate be awarded the relevant degree. Members of

Examination Committee are as follows:

Kamaruzaman Sijam, Ph.D.

Associate Professor

Faculty of Agriculture

Universiti Putra Malaysia

(Chairman)

Rosli Mohamad, Ph.D.

Professor



(Member)

Rita Muhamad, Ph.D.

Professor



(Member)

Isa Ipor, Ph.D.

Professor

Faculty of Resource Science & Technology

Universiti Malaysia Sarawak

(Member)

__________________________

Bujang Kim Huat, Ph.D.

Professor/ Deputy Dean

(Thesis and Academic Record)

School of Graduate Studies


Date:

xii

This thesis was submitted to the Senate of Universiti Putra Malaysia and has been

accepted as fulfillment of the degree of Master of Science. The members of the

Supervisory Committee were as follows:

Dzolkhifli Omar, Ph.D.

Professor



(Chairman)

Abdul Shukor Juraimi, Ph.D.

Associate Professor



(Member)

________________________________

Hasanah Mohd Ghazali, PhD

Professor and Dean

School of Graduate Studies


Date: 10 Jun 2010

xiii

DECLARATION

I hereby declare that the thesis is based on my original work except for quotations and

citations which have been duly acknowledged. I also declare that it has not been

previously or concurrently submitted for any other degree at Universiti Putra Malaysia or

other institutions.

____________________________

NORHAYATI BINTI NGAH

Date:

xiv

TABLE OF CONTENTS

Page

DEDICATION ii

ABSTRACT iii

ABSTRAK vi

ACKNOWLEDGEMENTS x

APPROVAL xi

DECLARATION xii

LIST OF TABLE xviii

LIST OF ABBREVIATION xxi

CHAPTER

1 INTRODUCTION 1

2 LITERATURE REVIEW

2.1 Weed 4

2.2 Chemical control 5

2.3 Entry and movement of herbicides in plants 6

2.4 Herbicide formulation 8

2.5 Herbicide application technique 10

2.6 Spray droplet size 12

2.7 Spray droplet densities 14

2.8 Spray droplet flight, deposition and retention on the target 14

2.9 Leaf surface characteristics 16

2.9.1 The leaf wax 16

2.9.2 The leaf surface roughness 19

xv

3 LEAF WAX AND SURFACE ROUGHNESS

3.1 Introduction 21

3.2 Materials and methods

3.2.1 Plant and Materials 21

3.2.2 Leaf wax extraction 23

3.2.3 Leaf area and leaf weight measurements 24

3.2.4 Leaf surface roughness 24

3.2.5 Quantification and qualification of 25

leaf surface roughness.

3.2.4 Experimental design and data analysis 26

3.3 Results and discussion

3.3.1 Mass of wax for both surface of leaf 27

3.3.2 Mass of wax for different surface of leaf 28

3.3.3 Quantification and qualification of

leaf surface roughness 30

3.4 Conclusion 34

4 EFFECT OF ROUGHNESS AND WAX ON LEAF SURFACE TO

DROPLET SPREAD OF GLYPHOSATE FORMULATIONS

4.1 Introduction 36

4.2 Materials and methods


4.2.2 Preparation of treatment solution 37

4.2.3 Measurement of spread area 38

4.2.4 Data analysis 39

4.3 Results and discussion

4.3.1 Droplet spread of glyphosate formulations 39

4.4 Conclusion 46

xvi

5 EFFECT OF ROUGHNESS AND WAX ON LEAF, SPRAY DROPLET

SIZES AND FORMULATION ON THE EFFECTIVENESS OF

GLYPHOSATE

5.1 Introduction 47

5.2 Materials and Methods


5.2.2 Measuring the spray deposition 49

5.2.3 Visual assessment 50

5.2.4 Fresh weight 51

5.2.5 Chlorophyll degradation 52

5.3 Data analysis 53

5.4 Results and Discussion

5.4.1 Spray deposition 53

5.4.2 Spray effectiveness 57

5.4.3 Fresh weight reduction 66

5.4.4 Chlorophyll degradation 68

5.5 Conclusion 77

CONCLUSIONS 78

REFERENCES 80

APPENDICES 90

BIODATA OF THE STUDENT 94

xvii

LIST OF TABLE

Table Page

3.1 Means comparison of epicuticular wax of broad leaves species 27

3.2 Means comparison of epicuticular wax of narrow leaves species 28

3.3 Means comparison of wax for abaxial and adaxial

surface on the selected plants species 29

3.4 The value of surface roughness 32

3.5 Distribution, number and length of hairs and trichome per mm² on upper surface of mature leaves for broad leaves plant 32

3.6 Size of epidermal cell on mature leaves for broad leaves plant 33

3.7 The value of surface roughness 34

3.8 Distribution, number and length of hairs and trichome per mm² on upper surface of mature leaves for narrow leaves plant 34

3.9 Size of epidermal cell on mature leaves for narrow leaves plant 35

4.1 Comparison of various formulation of glyphosate 38

4.2 Area of spread for all formulations using different droplet

volumes on different species of broad leaves plant 43

4.3 Area of spread for all formulations using different droplet

volumes on different species of narrow leaves plant 43

5.1 Spray treatments for evaluation on effect of formulation and

spray droplet sizes on the effectiveness of glyphosate 49

5.2 Visual weed control rating based on 0-100% 51

5.3 Effect of glyphosate formulations and droplet sizes on

spray deposition for broad leaves species 56


spray deposition for narrow leaves species 56


mortality on 3rd

DAT 61

xviii


mortality on 7th

DAT 61


mortality on 10th

DAT 62


mortality on 14th

DAT 62


mortality on 3rd

DAT 65


mortality on 7th

DAT 65


mortality on 10th

DAT 66


mortality on 14th

DAT 66

5.13 Effect of glyphosate formulations and droplet sizes on fresh

weight reduction for broad leaves species 68

5.14 Effect of glyphosate formulations and droplet sizes on fresh

weight reduction for narrow leaves species 68


chlorophyll content for broad leaves species at 3rd

DAT 72


chlorophyll content for broad leaves species at 7th

DAT 72


chlorophyll content for broad leavesspecies at 10th

DAT leaf 73


chlorophyll content for broad leaves species at 14th

DAT 73


chlorophyll content for narrow leaves species at 3rd

DAT 76


chlorophyll content for narrow leaves species at 7th

DAT 76

xix



DAT 77



DAT 77

xx

LIST OF ABBREVIATIONS

P. conjugatum Paspalum conjugatum

P. polistachyon Pennisetum polistachyon

I. cylindrica Imperata cylindrica

A. compressus Axonopus compressus

C. kylingia Cyperus kylingia

E. indica Eleusine indica

D. ocimifolia Diodia ocimifolia

C. hirta Clidemia hirta

A. gangetica Asystasia gangetica

C. rutidosperma Cleome rutidosperma

M. micrantha Mikania micrantha

B. latifolia Borreria latifolia

ANOVA Analysis of variance

CHCl3 Trichloromethane

CRD Complete Randomized Design

DAT Day after treatment

DSMA Disodiun methanearsonate

EPTC Ethyl di-n-prophylthiolcarbamate

HSD Tukey’s Studentized Range

MCPA Metaxon chloro phenyl acid

NPK Nitrogen, Phosphorous, and Potash

RCBD Randomized Complete Block Design

xxi

S.E Standart Error

SAS Statistical Analysis System

SEM Scanning electron microscope

UPM Universiti Putra Malaysia

1

CHAPTER 1

INTRODUCTION

Weeds reduce the yield of crop by suppressing plant growth through competition for

light, soil minerals, moisture and water. It was also lowering the quality of the harvest

through contamination with foreign matter. The damage is irreversible. In Malaysia,

herbicides usage was 67.49 percent of the total pesticide used equivalent to RM 218

million in 2004 (Omar, 2008). Farmers usually use a variety of methods to control the

weeds. The choice of methods is closely controlled by economics. The availability of

farm labor at the critical times needed for weeding crops is often limited, and herbicide

can often give more efficient weed control at comparable or even lower cost.

The efficiency of an herbicide application, while clearly depending on the chemical itself

as well as the formulation is also dependent upon being delivered to the target site

(Kirkwood, 1987). The application technique is the only means of improving targeting of

herbicide sprays and yet current understanding is relatively crude (Matthews, 2000).

Therefore, more research is needed to understand how spray and leaf structures interact to

enable more efficient placing of sprays at the target sites.

The activity of foliage applied herbicide must ultimately depend on the concentration of

active ingredient that reaches the sites of action together with the effect of the herbicide

on the biochemical mechanisms that take place at these sites. The micro structure of leaf

2

surfaces are among the factors that influence droplet retention. The amount of herbicide

deposited on a crop or weed canopy during the spray application is influenced by plant

morphological, spraying technique, herbicide formulation and environmental factors. The

plant factors included the habit of growth, size, shape, and orientation of the leaves, as

well as the characteristics of surface such as corrugation, roughness, and the presence of

hairs or trichomes and the physiochemical properties of the epicuticular waxes.

The epicuticular waxes are considered to be the first and main barrier to the penetration

of agriculturally important chemicals across the cuticle to their target site. The efficiency

of cuticle retention and penetration, tissue absorption and, in the case of systemic

compounds, herbicide metabolism or immobilization en route may reduce the amount

reaching the active sites. The surface topography also influences the behavior of

herbicide deposit on leaf surface. The surface roughness is an important factor to

determine the spray retention; it is responsible for droplet bounce by presenting surface

inclined from the horizontal, and governs the magnitude of contact angle hyteresis.

Roughness can cause droplets to coalesce to form larger deposits.

Spray deposition is generally proportional to the rate of application with losses occurring

due to runoff, volatility or spray misdirection; the height of the boom above the canopy

and the location of the leaves in the canopy may also influence surface deposits. Spray

volume and droplet size are also of considerable importance, presumably due to

interaction involving such factors as retention, spreading, wetting and penetration to the

surface of the foliage. In general, herbicidal efficiency increased with reduction in droplet

3

size. The optimal effect of herbicide spraying may be achieved when maximum contact

area is obtained by combination of small droplets and high volume. However, large

droplets maybe preferable in situations in which fine hairs are present on the plant surface

or where there is a need to exploit differential retention between a waxy crop and less

waxy weeds or between broad leaved plants and narrow leaved plant species.

Droplet size is undoubtedly a key issue; the smallest droplets being the most prone to

drift yet often being optimal for enhanced coverage, whereas larger droplets convey

excessive amounts of pesticide and may rebound from leaf surfaces. This results in poor

distribution, unless large volumes are applied to completely wet the surfaces which can

cause wastages. Further knowledge of the surface retention of droplets of different sizes

and their distribution, as well as information on the availability and persistence of

deposits on surfaces should provide a better specification for the type of nozzle required,

whether the spray liquid can be improved by including an appropriate adjuvant and

whether any additional delivery system such as air assistance should be used.

This research was carried out to study the effect of roughness and wax on leaf surfaces

and spray droplet sizes on the effectiveness of glyphosate. The study consisted of three

parts. Part one was the study on the leaf wax and surface roughness. The second part was

to study the effect of roughness and wax on leaf surface on spread droplet of glyphosate

formulations. Lastly, the study was conducted to evaluate the effect of roughness and

wax on leaf, spray droplet sizes and formulation on the effectiveness of glyphosate.

Documents

Influence of leaf surfaces and spray droplets on the ...psasir.upm.edu.my/12354/1/FP_2010_4A.pdf · morfologi permukaan daun, maka kekasaran permukaan daun dan lilin epicutikular