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Cotton Integrated Pest Management Research in Texas: Generating Ecologically-Based
Information
5th National Integrated Pest Management SymposiumApril 4-6, 2006
St. Louis, MO
Megha N. ParajuleeCotton Entomology Program
Texas Agricultural Experiment StationLubbock, Texas
Scope of Research in TX as a Scope of Research in TX as a Cotton EntomologistCotton Entomologist
Base acres: 3.0 millionLint harvest: 4.0 million balesFarm level value: >$1 Billion
High Plains Cotton Production60% of Texas25% of the U.S.5% of the world!World’s most
concentrated cotton production region
2525--County Texas High Plains; PCG/Cotton County Texas High Plains; PCG/Cotton Entomology Program Service AreaEntomology Program Service Area
TAMAULIPASTAMAULIPASTAMAULIPASTAMAULIPASTAMAULIPASTAMAULIPASTAMAULIPASTAMAULIPASTAMAULIPASTAMAULIPAS
BAJA BAJA BAJA BAJA BAJA BAJA BAJA BAJA BAJA BAJA CAL.CAL.CAL.CAL.CAL.CAL.CAL.CAL.CAL.CAL.
COAHUILACOAHUILACOAHUILACOAHUILACOAHUILACOAHUILACOAHUILACOAHUILACOAHUILACOAHUILACHIHUAHUACHIHUAHUACHIHUAHUACHIHUAHUACHIHUAHUACHIHUAHUACHIHUAHUACHIHUAHUACHIHUAHUACHIHUAHUA
SONORASONORASONORASONORASONORASONORASONORASONORASONORASONORA
VAVAVAVAVAVAVAVAVAVA
OKOKOKOKOKOKOKOKOKOK
TXTXTXTXTXTXTXTXTXTX
NCNCNCNCNCNCNCNCNCNC
SCSCSCSCSCSCSCSCSCSC
LALALALALALALALALALA
KSKSKSKSKSKSKSKSKSKS
ALALALALALALALALALAL
AZAZAZAZAZAZAZAZAZAZ ARARARARARARARARARAR
CACACACACACACACACACA
FLFLFLFLFLFLFLFLFLFL
GAGAGAGAGAGAGAGAGAGAMSMSMSMSMSMSMSMSMSMS
MOMOMOMOMOMOMOMOMOMO
NMNMNMNMNMNMNMNMNMNM
TNTNTNTNTNTNTNTNTNTN
El-Lissy, USDA-APHIS, 2005
Boll Weevil Eradication in the U.S. Boll Weevil Eradication in the U.S. 2005 Update2005 Update
CompletedEradication2005 Expansion
Transition to Post Boll Weevil Era
Still heavily relying on insecticides to manage cotton arthropods, augmented by use of IPM.
Lygus bugs are perceived as emerging pest problem.
Adoption of transgenic Bollgard technology in the Texas High Plains is in the rise (15%).
Natural enemy complex; alternate habitats.
General shift in production technology (cultivar, herbicide, tillage, irrigation).
Opportunities to use cultural and biological approaches to
pest management.
Progress (last 4-5 years)
1. Cotton aphid population dynamics modeling.2. Developing a natural enemy decision-rule
system.3. Economic evaluation of Bollgard cotton.4. Site-specific management of cotton arthropods.5. Areawide monitoring of bollworms, tobacco
budworms, and beet armyworms.6. Conservation tillage and cotton insects.7. Ecology and behavior of Lygus bugs.
1. Cotton aphid population dynamics modeling.2. Developing a natural enemy decision-rule
system.3. Economic evaluation of Bollgard cotton.4. Site-specific management of cotton arthropods.5. Areawide monitoring of bollworms, tobacco
budworms, and beet armyworms.6. Conservation tillage and cotton insects.7. Ecology and behavior of Lygus bugs.
Progress (last 4-5 years)
1. Cotton Aphid Population Dynamics Modeling
Fecundity
Survivorship
Temperature
Photoperiod
Nutrition
Predation
Crowding
2. Developing a Natural Enemy Decision-Rule System
0
20
40
60
80
0 50 100 150 2000
10
20
30
40
0 10 20 30 40
0
50
100
150
200
0 50 100 150 2000
50
100
150
200
0 100 200 300 400
Cot
ton
Aph
id C
onsu
mpt
ion
Cotton Aphid Density Cotton Aphid Density
Green Lacewing
Lady Beetle Small Larva Lady Beetle Large Larva
Lady Beetle Adult
Cotton Aphid Suppression
Field Cage Study
Effectiveness at:
1 aphid/leaf (1 LB/Plant)
25 aphids/leaf (3 LB/Plant)
50 aphids/leaf (6 LB/Plant)
0
100
200
300
400
500
600
0 1 2 3 4 5 6 7 8 9
ControlLB at 50 aphids/leaf
LB at 25 aphids/leafLB at 1 aphid/leaf
Aphid Population Suppression by Convergent Lady Beetle Larva in
Cages, Lubbock, July-August, 2003A
vg. A
phid
s/Le
af
Weeks After Predator Introduction
Economic Threshold: 50 aphids/leaf for two weeks
3. Economic Evaluation of Bollgard Cotton for the
Texas High Plains
x
x
Two locationsIdalouHalfway
Three cultivars Roundup ReadyBollgardBollgard II
Bollgard Technology Evaluation, Untreated Cotton, Idalou, TX 2004
0
1000
2000
3000
4000
FM 960RFM 960BRFM 960B2R
Bollworm larvae >3 days oldSeason average
Bol
lwor
m L
arva
e/A
cre a
b b
86%100%
August 4 peak8,493 larvae/A
Bollgard Technology Evaluation, Untreated Cotton, Idalou, TX 2004
0
1000
2000
3000
4000
5000
6000
FM960R FM960BR FM960B2R
Minor damageYield damage
Fru
itin
g Fo
rms/
Acr
e
Damaged bolls
aB
b
A
b B
Is Bollgard Technology Fit for the Texas High Plains?
Both Bollgard and Bollgard II control bollworms around our threshold of 10,000 small larvae per acre.
Bollgard II is also effective against beet armyworms, fall armyworms, and pink bollworms.
Bollgard technology is certainly a good pest management insurance policy (≈15% adoption).
4. Site-Specific Management of Cotton Arthropods
5. Areawide Monitoring of Bollworm, Budworm, and Beet Armyworm Moths
Weekly survey of three counties throughout the year.
Summary information provided to target clientele through the electronic newsletter FOCUS on Entomology.
6. Conservation Tillage and Arthropod Management
7. Ecology and Behavior of Lygus Bugs
A Model for Cultural Management of
Arthropods in Cotton
Identification of problems: extensive survey work.Host plant preference and suitability.Scope of damage; plant compensation.Plant susceptibility window-when is fruit safe?Insect behavior: intra-host movement.Insecticide efficacy, resistance issues.Understanding behavior and ecology at molecular level.
7. Ecology and Behavior of Lygus Bugs
Areawide Survey:Host Plant Sequencing
318,709 sweep samples55,000 cotton
65,488 Lygus adults21,873 Lygus nymphs
2002-2005
Lygus Host PlantsCommon Name Scientific NameAlfalfa Medicago sativaBlack mustard Brassica nigraBlue mustard Chorispora tenellaCurly dock Rumex crispusField bindweed Convolvulus arvensisFlixweed Descurainia sophiaHorseweed Conyza canadensisKochia Kochia scopariaLambsquarters Chenopodium spp.London rocket Sisymbrium irioPigweed Amaranthus spp.Ragweed Ambrosia spp.
Lygus Host Plants
Common Name Scientific NameRedstem filaree Erodium cicutariumRussian thistle Salsola ibericaSilverleaf nightshade Solanum elaeagnifoliumSmartweed Polygonum spp.Texas blueweed Helianthus ciliarisTumble mustard Sisymbrium altissimumWild sunflower Helianthus annuusWoolyleaf bursage Ambrosia grayiYellow sweetclover Melilotus officinalisCotton Gossypium hirsutum
01-50
51-100101-500
>500
2002 2003
Flixweed
Lygus/100 sweeps
Host Plant Sequence
0
200
400
600
800
1000
1200
4 7 10 13 16 19 22 25 28 31 34 37 40 43 46
No.
Lyg
uspe
r 100
sw
eeps
APR MAY JUN JUL AUG SEP OCT NOVJAN FEB MAR
2002-2003 MustardAlfalfaPigweedRussian thistle
0
10
20
30
40
50
60
70
80
90
100
4 7 10 13 16 19 22 25 28 31 34 37 40 43 46
No.
Lyg
uspe
r 100
sw
eeps
APR MAY JUN JUL AUG SEP OCT NOVJAN FEB MAR
Cotton-2003
Lygus Host Preference
Pigweed
SunflowerAlfalfa
Russian thistleCotton
Dominant Non-cotton Hosts and
Cotton
Mosaic of Dominant Hosts and Cotton:Replica of the Texas High Plains!
Species Composition in the Population
2%
1%
97%
Lygus hesperus
Lygus elisus
Lygus lineolaris
Species identification were based upon keys for adult males.
Colonization/Seasonal Abundance L. hesperus adults
0
10
20
30
40
50
60
A S O N
Russian Thistle
Alfalfa
Pigweed
Sunflower
Cotton
Aug Sep Oct Nov
Nu
mbe
r pe
r 5
0 s
wee
ps
Alfalfa Mowed
0
10
20
30
40
50
60
70
A S O N
Russian ThistleAlfalfaPigweedSunflowerCotton
Aug Sep Oct Nov
Nu
mbe
r pe
r 5
0 S
wee
ps
Alfalfa Mowed
Reproduction/Seasonal Abundance L. hesperus nymphs
Cotton Compensation of Lygus Induced Fruit Loss
Lygus nymphs (2nd instar) released weekly for three consecutive weeks, 2005.
Experimental Protocol
Early bloom(July 16-August 10)
Treatments:
0 Lygus achieved through insecticide control
0 Lygus released (natural control)
1 Lygus per plant
3 Lygus per plant
COTMAN and plant mapping performed.
Lygus Bugs Released
0
10
20
30
40
50
60
Week2 Week3 Week4 Week5
SC NC 1PP 3PP
Percentage Fruit LossLubbock, Texas, 2005Early Bloom Release
% F
ruit
Los
s
July 16 July 24 August 2 August 11
Bugs Released
a
bb
c
aa
b
c
S S S
S=Sprayed
S SS SNS
aa
bb
Yie
ld (
lbs/
Acr
e)
400
500
600
700
SC NC 1PP 3PPa a
a
b
215 lbs
Lint Yield from the First Fruiting PositionLubbock, Texas, 2005
Total Lint Yield: Compensation StudyLubbock, Texas, 2005
Yie
ld (
lbs/
Acr
e)
600
700
800
900
1000
SC NC 1PP 3PP
aab ab
b
127 lbs
When is a cotton boll safe from
Lygus damage?
Measuring carpel wall toughness using a penetrometer
Lygus external probing Damage inside the boll
Regression Analysis Predicting Boll Susceptibility, PM 2326RR
y = -0.0031x + 4.7287R2 = 0.92
0.0
0.5
1.0
1.5
2.0
2.5
3.0
800 1000 1200 1400 1600
No.
In
ner
Car
pel
Wal
l War
ts
Pressure (Grams/mm2)
Current Projects
Use of a more precise penetrometer to refine the boll suceptibility cut-off value.
Evaluate boll susceptibility differences due to irrigation and cultivar.
Boll Susceptibility StudyUse of Commercial Penetrometer
Behavioral bioassays using a multi-choice olfactometer.
Potential chemistry work to determine kairomone or other plant constituents for host preference.
Behavioral BioassayMulti-Choice Olfactometer
Bioassays to determine baseline susceptibility to potential insecticides.Temporal and spatial monitoring of potential resistance to commonly used insecticides.
Insecticide EfficacyResistance Issues
Restriction Fragment Length Polymorphism (RFLP).
Amplified Fragment Length Polymorphism (AFLP).
Microsatellite markers.
Behavioral Ecology of Lygus at Molecular Level
Molecular Systematics and Phylogeography
Behavioral Ecology of Lygus at Molecular Level
Insect Movement between Cotton and Non-cotton Hosts
Data acquisitionProtein markers Spraying of markers
Acknowledgments