published by utah state university extension and …...chinch bugs damage turfgrass leaves with...

Published by Utah State University Extension and Utah Plant Pest Diagnostic Laboratory September 2013ENT-169-13PR

Chinch BugsKelly Kopp, Extension Water Conservation and Turfgrass Specialist, Ryan S. Davis, Arthropod Diagnostician,

and Ricardo A. Ramirez, Extension Entomologist

DO YOU KNOW

• ChinchbugsareoccasionalpestsofturfgrassinUtah.

• ChinchbugsfeedonavarietyofturfgrassspeciesincludingKentuckybluegrass,perennialryegrass,thefescues,bentgrassandzoysiagrass.

• Damageisusuallyheaviestinsunnylocationsduringhot,dryperiods.

• Soundcultural(non-chemical)practicesarethebestdefenseagainstchinchbugdamage.

Figure1.Adultchinchbug.

INTRODUCTIONChinchbugs(Fig.1)are“truebugs”.InUtah,thecommonchinchbug[Blissusleucopterusleucopterus(Say)],andwesternchinchbug(Blissus occiduus)mayfeedonturfgrass,especiallyunderconditionsofsevereheatanddrought.Coupledwithunder-irrigation,directsunlight,andthickthatch,chinchbugnumberscansoarfrommid-summertoearlyfall.

Adultsoverwinterinthatch,clumpsofgrass,nexttobuildingsandalongtheedgesofsidewalks.Theyemergeinearlyspringtomate(whentemperaturesreach70ºF).Femalesinserteggsonundergroundroots,behindleafsheathsinthecrownsofturfplants,inthefoldsofgrassblades,orinthethatch.Eggshatchinmidtolatespringwithdevelopmentofimmaturestagesrequiringapproximately1month.Adultsofthefirstsummergenerationbegintoappearinearlytomidsummer.Eggsofthesecondsummergenerationhatchapproximately1monthlaterandcompletedevelopmentinearlytomidfall.Adultsof

BIOLOGY thisgenerationmovetooverwinteringsitesastemperaturescoolinthefall.

IDENTIFICATIONChinchbugsgothroughnumerousdevelopmentalstages(Fig.2).Firststagenymphsofthecommonchinchbugaretiny(1/64in)andbrightredwithawhitebandacrosstheabdomen(Fig.2).Astheymaturethroughfivenymphalstages,theyturnorange-brownandthenblack.Adultsareblack(1/10inlong)andwhitewithfullydevelopedwingsthatfoldoverthebackandextendtotheendoftheabdomen(Figs.1&2).Thiscreatesablacktrianglepatternbehindthepronotum

Actualadultlength

Chinchbugsdamageturfgrassleaveswithpiercing-suckingmouthparts,inhibitingtransportofwaterwithintheplant.Patchydiebackisfollowedbylargerareasofdamage.Inseverecases,completelawnlossmayoccur(Fig.5).Chinchbugfeedingdamagecanoftenresembledroughtstress;damageisoftenworseonplantsthatarealreadyaffectedbydrought.Chinchbugdamagewillnotrespondtoincreasedwateringasadrought-affectedlawnwould.

DAMAGE

Actualadultlength

Figure2.Immature(nymph)andadultchinchbugs.

(“shoulders”),pointingtowardtherear.Somepopulationsofadultchinchbughavereduced-sizedwingsasadults.Whencrushed,chinchbugsemitafoulodorlikestinkbugs(Vittumetal.,1999).

Thereareseverallook-alikeinsectsthatcanalsobefoundinturf.Bothbig-eyedbugs(Fig.3)andminutepiratebugs(Fig.4)arebeneficialpredatorsandshouldbepreserved.FalsechinchbugsalsoappearsimilartochinchbugsbutrarelyoccurinturfgrassinUtah.

andimidacloprid.Withcurativeproducts,likebifenthrin,thegoaloftheiruseistocoverturfgrassstemsandtheupperthatchsothatthechinchbugsarecontrolledbydirectcontact.Lightirrigationmayalsohelptomoveliquidinsecticidesdownintothethatchlayerwherechinchbugsreside.Ifthethatchandsoilareverydry,irrigatingonthedaypriortoinsecticideapplicationmaybewarranted.Ifgranularproductsareused,thefoliageshouldbedrysothattheprillsdon’tsticktotheleavesandreachtheupperthatch.Lightirrigationfollowinggranularinsecticideapplicationisalsorecommended(Potter,1998).

Preventivetreatment,usingsystemicproductslikeimidacloprid,forchinchbug

Figures3&4.Chinchbuglook-alikes.Big-eyedbug(top);minutepiratebug(bottom).Bothinsectsarebeneficialpredators.

Hands-and-Knees Method

Thesimplestmethodfordetectingandmonitoringchinchbugsisthe“handsandknees”method.Usingyourthumbsandfingers,pullbackgrassstemstoexposethecrownsandthatchwherechinchbugadultsandnymphsmaybehiding.Thenymphsareverytiny,however,andmaybeeasilyoverlooked(Fig.6).Asconditionsbecomewarmanddrier,chinchbugsmaymovedeeperinthethatch.Becausetheyaresosmall,ahandlensormagnifyingglassmaybeneededtoseethem.Visualobservationofdrivewaysandsidewalksadjacenttodamagedturfareasonhotafternoonsoftenrevealsadultchinchbugsrunningacrossthepavement.Adultchinchbugsmayalsobeobservedcrawlingonthesidesoflight-coloredbuildingsundertheseconditions.Chinchbugsshouldnotbeconfusedwithsimilarlooking,beneficialinsectslikeminutepiratebugsandbig-eyedbugs(Figs.3&4).

MONITORING

Figure5.Severechinchbugdamagemayleadtocompletelossofturfgrass.

Figure6.Chinchbugnymphsareverysmallandeasilyoverlooked.

Chinchbugsandtheirdamagegenerallyoccurinscatteredpatchesinturfgrass.Populationsmayreach200to300bugspersquarefeetinheavilyinfested,sunnyareas.DamageistypicallyvisiblefromlateJunethroughAugustwhentheoldersummergenerationnymphsandadultsarefeeding(NiemczykandShetlar,2000).DamagemaybeseenearlierinsouthernUtah.

“Floatation” Trap

A“floatation,”traptomonitorchinchbugscanbemadefroma6-inchdiametercoffeecanorsimilarobjectwithbothendsremovedtocreateametalcylinder.Pushthecanintothesoilapproximately2to3inchesdeep,enclosingtheturfandfillthecanabout¾fullofwater.Pokeorstirtheturfandthatchthatisunderwaterkeepingaconstantdepthofwaterinthecanforabout10minutesbypouringinextrawatertoreplacethelost/leachingwater.Countthenumberofchinchbugsthatfloattothesurface.

CONTROL

Cultural Control

Emphasizinghealthyturfisrecommendedtodiscouragechinchbuginfestations.Usethefollowingculturalcontrolmethodstominimizechinchbugdamage:

• Aerateonceortwiceperyeartoreducethatch,especiallyinlawnspronetothatchdevelopment.

• Ifchinchbugdamageisnotsevere,adequateirrigationandlightfertilizationapplicationscanencourageturfgrassrecoveryandtolerance(Potter,1998).

• EncouragemoistsoiltofosterthegrowthofBeauveriafungus,anaturalbioticpathogenofchinchbug.Conversely,applicationoffungicides

UtahStateUniversityiscommittedtoprovidinganenvironmentfreefromharassmentandotherformsofillegaldiscriminationbasedonrace,color,religion,sex,nationalorigin,age(40andolder),dis-ability,andveteran’sstatus.USU’spolicyalsoprohibitsdiscriminationonthebasisofsexualorientationinemploymentandacademicrelatedpracticesanddecisions.UtahStateUniversityemployeesandstudentscannot,becauseofrace,color,religion,sex,nationalorigin,age,disability,orveteran’sstatus,refusetohire;discharge;promote;demote;terminate;discriminateincompensation;ordiscriminateregardingterms,privileges,orconditionsofemployment,againstanypersonotherwisequalified.Employeesandstudentsalsocannotdiscriminateintheclassroom,residencehalls,orinon/offcampus,USU-sponsoredeventsandactivities.ThispublicationisissuedinfurtheranceofCooperativeExtensionwork,actsofMay8andJune30,1914,incooperationwiththeU.S.Dept.ofAg.,NoelleE.Cockett,VicePresidentforExtensionandAgriculture,UtahStateUniversity.

Page4UPPDL,5305OldMainHill,LoganUT84322,utahpests.usu.edu T:435.797.2435F:435.797.8197

Precautionary Statement:UtahStateUniversityExtensionanditsemployeesarenotresponsiblefortheuse,misuse,ordamagecausedbyapplicationormisapplicationofproductsorinformationmentionedinthisdocument.Allpesticidesarelabeledwithingredients,instructions,andrisks,andnotallareregisteredforediblecrops.“Registereduse”pesticidesmayonlybeappliedbyalicensedapplicator.Thepesticideapplicatorislegallyresponsibleforproperuse.USUmakesnoendorsementoftheproductslistedherein.

Figure 1.ImagecourtesyofGrahamMontgomery,CornellUniversity. Figure 2.ImagecourtesyofSamuelAbbott,UtahStateUniversity.Figures 3&4.ImagescourtesyofBradleyHigbee,ParamountFarming,Bugwood.org.Figure 5.ImagecourtesyofKatieWagner,UtahStateUniversityCooperativeExtension,SaltLakeCounty.Figure 6. ImagecourtesyofNatalieHummel,LouisianaStateUniversityAgCenter.

-Davis,R.Fall2012.Turfageddon:Thechinchbuginvasion.UtahPestsNews.Vol.VI.http://utahpests.usu.edu/htm/utah-pests-news/up-fall-2012-newsletter/chinch-bug-invasion/(accessedNov.2012).-Niemczyk,H.D.,andD.J.Shetlar.2000.Destructiveturfgrassinsects(2ndEd.).H.D.N.Books,Wooster,OH.-Potter,D.A.1998.Destructiveturfgrassinsects:biology,diagnosis,andcontrol.AnnArborPress,Chelsea,MI.-Vittum,P.J.,M.G.Villani,andH.Tashiro.1999.TurfgrassinsectsoftheUnitedStatesandCanada(2ndEd.).CornellUniversityPress,Cornell,NY.-Sheltar,D.J.,andAndon,J.2011.ChinchBugsinTurfgrass.EntomologyFactSheet,HYG-2503-11.TheOhioStateUniversity.

FactSheetSeries:Insects—Turf

IMAGES & REFERENCES

maysuppressBeauveriaandfavorthebuildupofchinchbugpopulations.

• Fertilizeregularlytoimpartsomeresistanceofturfgrasstochinchbugdamage.

• Plantoroverseedturfwithendophyte-enhancedcultivarsofperennialryegrass,fine-leaffescueortallfescuewhichareresistanttochinchbugsandcommonturfdiseases.

• Kentuckybluegrasslawnswithahighpercentageofnon-endophyticfine-leaffescueand/orperennialryegrass,andlawnswithexcessivethatch,areespeciallysusceptibletochinchbugdamage(Potter,1998).

Chemical Control

AnumberofinsecticidesarelabeledforcontrolofchinchbuginUtah.Forhomeowners,thereareseveralactiveingredientssuchasbifenthrin,lambda-cyhalothrin,cyfluthrinandimidaclopridthatareavailable.Forcommercialapplicators,inadditiontoactiveingredientsavailableforhomeowners,clothianidin(Arena;non-restricteduse)andseveralrestricted-useproductsthattypicallycontainacombinationofpyrethroidsandneonicotinoidsarealsoavailable(Aloft,Allectus).

Withcurativeproducts,typicallypyrethroids(e.g.,bifenthrin),thegoalistocoverturfgrassstemsandtheupperthatchlayersothatthechinchbugsarecontrolledbydirectcontact.Preventivetreatment,usingsystemicproductslike

neonicotinoids(e.g.,imidacloprid)thatmoveintotheplant,isgenerallynotwarrantedaschinchbugsrarelycausesufficientdamageinUtah.Ifchinchbugsarepositivelyidentifiedasthecauseofseveredamage,thenspot-treatmentofinfestedareasisabetteroptiontocontroltheirpopulation.

Turfinsecticidesmaycomeinliquidorgranularform.Withliquidformulations,irrigationshouldbeavoidedforseveraldaysafterapplicationtoallowtheinsecticidetocontactthebladesofgrassandthatchwherechinchbugsreside.Somelabelsmay,however,recommendlightirrigationtomoveliquidinsecticidesdownintothethatchlayer.Ifthethatchandsoilareverydry,irrigatingonthedaypriortoinsecticideapplicationmaybewarranted.Whenusinggranularformulations,thefoliageshouldbedrysothattheprillsdonotsticktotheleavesandreachstemsandtheupperthatchlayer.Lightirrigationfollowinggranularinsecticideapplicationisrecommended(Potter,1998).

Treatment Thresholds

Infestationsof20to25nymphspersquarefootaregenerallyconsidereddamagingenoughtowarrantcontrol.Usingthe“floatation”techniquementionedabove,estimatethenumberofnymphsfoundpersquarefootbasedontheareacoveredbythecan.Ifnymphnumbersarebelowthisthreshold,regularirrigationandfertilizationcanmitigatechinchbugdamage.