Pesticide Resistance:Pesticide Resistance: Can It Happen in Turf?Can It Happen in Turf?

Eileen A. BussEileen A. BussAssociate Professor & Extension Associate Professor & Extension

SpecialistSpecialist

Entomology & Nematology Dept. Entomology & Nematology Dept.

Resistance in Ornamental, Resistance in Ornamental, Vegetable and Fruit PestsVegetable and Fruit Pests

AphidsAphids

BeetlesBeetles

CaterpillarsCaterpillars

LeafminersLeafminers

PlanthopperPlanthopperss

ScalesScales

Spider mitesSpider mites

Stink bugsStink bugs

ThripsThrips

WhitefliesWhiteflies

Brief History…Brief History…

Cases of resistance to several key Cases of resistance to several key pests developed within 2-20 years pests developed within 2-20 years after the introduction of the after the introduction of the cyclodienes, organophosphates, cyclodienes, organophosphates, carbamates, pyrethroids, Bacillus carbamates, pyrethroids, Bacillus thuringiensis, spinosyns, and thuringiensis, spinosyns, and neonicotinoids.neonicotinoids.

Resistance MechanismsResistance Mechanisms

1.1. Metabolic resistanceMetabolic resistance

2.2. Target site insensitivityTarget site insensitivity

3.3. Reduced penetrationReduced penetration

4.4. Behavioral resistanceBehavioral resistance

Resistance MechanismsResistance Mechanisms

1.1. Metabolic resistanceMetabolic resistance Resistant insects break down the Resistant insects break down the

toxin faster than susceptible insects toxin faster than susceptible insects can. can.

Resistance MechanismsResistance Mechanisms

2. Target site insensitivity2. Target site insensitivity The site where the toxin binds in the The site where the toxin binds in the

insect has changed.insect has changed.

Resistance MechanismsResistance Mechanisms

3. Reduced penetration3. Reduced penetration Resistant insects may absorb Resistant insects may absorb

the toxin slower through the the toxin slower through the cuticle than susceptible insects cuticle than susceptible insects can.can.

Resistance MechanismsResistance Mechanisms

4. Behavioral resistance4. Behavioral resistance Resistant insects may detect Resistant insects may detect

and behaviorally avoid the and behaviorally avoid the toxin.toxin.

Resistance in Turf PestsResistance in Turf Pests

Annual bluegrass weevil Southern chinch bugAnnual bluegrass weevil Southern chinch bug

Lyle Buss, UF/IFAS

Is pesticide Is pesticide resistance more resistance more likely to develop in likely to develop in home lawns or golf home lawns or golf courses?courses?

Is pesticide Is pesticide resistance more resistance more likely to develop in likely to develop in home lawns or golf home lawns or golf courses?courses?

It depends more on It depends more on the pest’s biology the pest’s biology and the intensity of and the intensity of management management against it.against it.

Other turf pests that Other turf pests that have have potentialpotential to to

become resistant… become resistant…

(but nothing is documented (but nothing is documented yet!)yet!)

Fall armyworm egg mass on tree leaf.Fall armyworm egg mass on tree leaf. FAW egg mass on post.FAW egg mass on post.

FAW larva showing white Y-mark on head.FAW larva showing white Y-mark on head.FAW adult male.FAW adult male.

J. Castner, UFJ. Castner, UF

Hunting Hunting Billbug Billbug

Life Life CycleCycle

What About Mole Crickets?What About Mole Crickets?

Speed of Resistance Speed of Resistance DevelopmentDevelopment

Depends on: Depends on: how fast the insects reproducehow fast the insects reproduce migration and host range of the pestmigration and host range of the pest availability of nearby susceptible availability of nearby susceptible

populationspopulations persistence and specificity of the persistence and specificity of the

pesticidepesticide rate, timing and number of applications rate, timing and number of applications

mademade

The “Pesticide Treadmill”The “Pesticide Treadmill”

After repeated applications, pests evolve After repeated applications, pests evolve resistance to the insecticide and the resistant resistance to the insecticide and the resistant strain becomes harder to manage at the strain becomes harder to manage at the labeled rate and frequency. labeled rate and frequency.

Thus, the insecticide is applied more Thus, the insecticide is applied more frequently. frequently.

Resistance intensity and the frequency of Resistance intensity and the frequency of insecticide-resistant individuals in the insecticide-resistant individuals in the population both increase and control failures population both increase and control failures continue as yet more product is applied. continue as yet more product is applied.

Users switch to another pesticide.Users switch to another pesticide.

History of Insecticide Resistance History of Insecticide Resistance in the Southern Chinch Bugin the Southern Chinch Bug

1953: Chlordane1953: Chlordane

1957: DDT1957: DDT

1960: Parathion1960: Parathion

1976: Chlorpyrifos, Diazinon, 1976: Chlorpyrifos, Diazinon, TrichlorfonTrichlorfon

2005: Bifenthrin2005: Bifenthrin

Why Control Failures OccurWhy Control Failures Occur Application errorsApplication errors Misidentification of pest or damageMisidentification of pest or damage Improper control timingImproper control timing Use of wrong rate or formulationUse of wrong rate or formulation Inadequate spray volume/irrigationInadequate spray volume/irrigation Improper spray solution pHImproper spray solution pH PhotodegradationPhotodegradation VolatilizationVolatilization Microbial degradationMicrobial degradation Insect resistanceInsect resistance

Goal:Goal:

Reduce the selection Reduce the selection pressure on the pest.pressure on the pest.

How to Develop a Resistance How to Develop a Resistance Management PlanManagement Plan

1. Learn about IPM strategies and 1. Learn about IPM strategies and create a season-long plan to create a season-long plan to minimize pesticide applications. minimize pesticide applications.

D. Potter, UKYD. Potter, UKY

Best Management Practices

A Successful IPM Program A Successful IPM Program Depends on:Depends on:

Knowledge of pest biologyKnowledge of pest biology Monitoring and estimating pest densityMonitoring and estimating pest density Knowledge of economic/aesthetic injury Knowledge of economic/aesthetic injury

levels (i.e., action thresholds)levels (i.e., action thresholds) Everyone needs to tolerate some insects or Everyone needs to tolerate some insects or

their damage (threshold should not = 1 bug)their damage (threshold should not = 1 bug) Change from routine or “preventive” Change from routine or “preventive”

applications to as-needed applications to as-needed

How to Develop a Resistance How to Develop a Resistance Management PlanManagement Plan

2. When designing, installing, or renovating, 2. When designing, installing, or renovating, select plant species or cultivars that are select plant species or cultivars that are resistant to insect attack.resistant to insect attack.

Host Plant ResistanceHost Plant Resistance

Cultivars of different turfgrass species Cultivars of different turfgrass species have been screened for resistance to:have been screened for resistance to: Fall armywormFall armyworm

Japanese beetleJapanese beetle

Mole cricketsMole crickets

Chinch bugsChinch bugs

Bermudagrass mitesBermudagrass mites

BillbugsBillbugs

How to Develop a Resistance How to Develop a Resistance Management PlanManagement Plan

3. Use as many different control 3. Use as many different control methods as possible.methods as possible.

Use a variety of synthetic and Use a variety of synthetic and biorational insecticidesbiorational insecticides

Conserve or release beneficial insectsConserve or release beneficial insects

Adjust cultural practicesAdjust cultural practices

Use chemical attractants / deterrentsUse chemical attractants / deterrents

Natural EnemiesNatural Enemies

Parasitic wasps, fliesParasitic wasps, flies Big-eyed bugsBig-eyed bugs Minute pirate bugs Minute pirate bugs Damsel bugsDamsel bugs EarwigsEarwigs Ground beetlesGround beetles Rove beetlesRove beetles Several ant speciesSeveral ant species SpidersSpiders

Possible Cultural ControlsPossible Cultural Controls

Alter amount / frequency of irrigationAlter amount / frequency of irrigation

Reduce thatch thicknessReduce thatch thickness

Adjust amount/frequency of fertilizationAdjust amount/frequency of fertilization

Irrigation / Moisture Irrigation / Moisture ManagementManagement

Insect eggs and immatures need Insect eggs and immatures need water / humidity to survivewater / humidity to survive

Reduce watering to desiccate the pestsReduce watering to desiccate the pests Increase watering to drown them outIncrease watering to drown them out

Drought Stress / IrrigationDrought Stress / Irrigation

Chemical Application / Formulation?Chemical Application / Formulation? What formulation will work best in this What formulation will work best in this

situation? situation? Granular / Fertilizer carrierGranular / Fertilizer carrier SprayableSprayable

Flexibility?Flexibility? Does the spray technician have flexibility Does the spray technician have flexibility

to choose between formulations, to choose between formulations, depending on an individual situation?depending on an individual situation?

Heavy Fertilization…Heavy Fertilization…

Attracts female moths that are ready to Attracts female moths that are ready to lay eggslay eggs

Increases thatch Increases thatch Improves habitat for thatch-dwelling pestsImproves habitat for thatch-dwelling pests

Makes turf more succulent Makes turf more succulent Insects could pierce the plants more easilyInsects could pierce the plants more easily

Importance of Nitrogen (N)Importance of Nitrogen (N)

Nitrogen content in host plants influences Nitrogen content in host plants influences insect survival, development time, body insect survival, development time, body size, and reproduction size, and reproduction (Mattson 1980, McNeill & (Mattson 1980, McNeill & Southwood 1978)Southwood 1978)

Increasing N fertilization reduces plant Increasing N fertilization reduces plant resistance to some insect species (esp. resistance to some insect species (esp. beetles and moths) beetles and moths) (Barbour et al. 1991)(Barbour et al. 1991)

Southern chinch bug damage seems Southern chinch bug damage seems related to increased ammonium nitrate use related to increased ammonium nitrate use (Horn and Pritchett 1962, Busey and Snyder 1993)(Horn and Pritchett 1962, Busey and Snyder 1993)

How to Develop a Resistance How to Develop a Resistance Management PlanManagement Plan

4. Carefully select insecticides4. Carefully select insecticides Consider more than cost & effectivenessConsider more than cost & effectiveness

Beneficial insectsBeneficial insects Product classProduct class Rates and treatment intervalsRates and treatment intervals Product application methodsProduct application methods Tank mixesTank mixes Timing of applicationsTiming of applications

Which Products to Use: Which Products to Use: Practical ConsiderationsPractical Considerations

Choice is limited by:Choice is limited by: Crop / use siteCrop / use site

Number of applications / Number of applications / amount of product allowed for amount of product allowed for useuse

Sensitivity of the plant speciesSensitivity of the plant species

Vary the Mode of Action (MoA)Vary the Mode of Action (MoA)

Insecticides act on different Insecticides act on different physiological and biochemical target physiological and biochemical target sites in insects to kill themsites in insects to kill them Nervous systemNervous system (e.g., neurotransmitters, (e.g., neurotransmitters,

receptor sites)receptor sites)

Growth and developmentGrowth and development (e.g., hormones) (e.g., hormones)

Energy productionEnergy production (e.g., prevent feeding) (e.g., prevent feeding)

Possible Rotation ProductsPossible Rotation Products PyrethroidsPyrethroids (Group 3) (Group 3)

Bifenthrin (Talstar/Onyx), Beta-cyfluthrin Bifenthrin (Talstar/Onyx), Beta-cyfluthrin (Tempo), Deltamethrin (DeltaGard), (Tempo), Deltamethrin (DeltaGard), lambda-cyhalothrin (Scimitar)…lambda-cyhalothrin (Scimitar)…

Carbamates and Carbamates and OrganophosphatesOrganophosphates (Groups 1 A and (Groups 1 A and B)B) Carbaryl (Sevin) and trichlorfon (Dylox)Carbaryl (Sevin) and trichlorfon (Dylox)

NeonicotinoidsNeonicotinoids (Group 4A)(Group 4A) Clothianidin (Arena), imidacloprid (Merit)Clothianidin (Arena), imidacloprid (Merit)

Reduced-Risk Reduced-Risk (Biorational) Insecticides(Biorational) Insecticides

Molt-accelerating Molt-accelerating compounds and other IGR’scompounds and other IGR’s Mach2Mach2

Dimilin 2LDimilin 2L

ConfirmConfirm

Microbial insecticides Microbial insecticides Bt, Conserve, insect-parasitic Bt, Conserve, insect-parasitic

nematodesnematodes

Entomopathogenic Entomopathogenic NematodesNematodes

Several species Several species ((SteinernemaSteinernema spp., spp., HeterorhabditisHeterorhabditis spp.) spp.) occur naturally in the soil, occur naturally in the soil, but some can be but some can be purchasedpurchased

Some insecticides, like Some insecticides, like imidacloprid (Merit), may imidacloprid (Merit), may slow grub behavior down slow grub behavior down and make them more and make them more susceptible to nematode susceptible to nematode infectioninfection

Getting the Best Chemical Getting the Best Chemical ControlControl

Properly calibrate and maintain equipmentProperly calibrate and maintain equipment

Rotate insecticides with different modes of Rotate insecticides with different modes of actionaction

Use enough volume to penetrate thatchUse enough volume to penetrate thatch

Add an adjuvant to improve coverage, if Add an adjuvant to improve coverage, if neededneeded

Don’t spray if rain could wash product offDon’t spray if rain could wash product off

Application Issues…Application Issues…

Photos by R. Clemenzi, Photos by R. Clemenzi, Bayer Environmental Bayer Environmental ScienceScience

Application IssuesApplication Issues Granular / Formulated productsGranular / Formulated products

Spreader placementSpreader placement Tire on sidewalk vs. Tire on grass Tire on sidewalk vs. Tire on grass edgeedge

Photo by R. Clemenzi, Photo by R. Clemenzi, Bayer Environmental Bayer Environmental ScienceScience

Application IssuesApplication Issues

Photo by R. Clemenzi, Photo by R. Clemenzi, Bayer Environmental Bayer Environmental ScienceScience

Online ResourceOnline Resource

Insecticide Resistance Action Insecticide Resistance Action Committee (IRAC) website: Committee (IRAC) website: www.irac-online.org

Eileen BussEileen Buss

352-273-3976352-273-3976

eabuss@ufl.edueabuss@ufl.edu