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

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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

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20

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40

0 10 20 30 40

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50

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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

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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

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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

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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