Organic Solutions for Harlequin Bugs and Other Stink Bugs

A Factsheet from Toxic Free NC

AboutHarlequinBugsandS4nkBugsTheHarlequinbugisatypeofs5nkbugthatcausestroubleformanygardenersintheSoutheast.Others5nkbugpestsinNorthCarolinaincludetheGreens5nkbug,Browns5nkbug,andSoutherngreens5nkbug.Allarepestsofmanycrops,buttheyespeciallyloveplantsofthebrassicafamily.Thebrassicasincludecabbage,collards,broccoli,mustard,turnips,andkale.Duringheavyoutbreaks,orwhenalltheirfavoritesaregone,Harlequinbugswilleatothergardenplantssuchassquash,okra,tomatoes,corn,beans,andtreefruits.Bothadultsandnymphscausedamage.Theyeatallpartsoftheplants,includingstems,leaves,fruits,andseeds.Theyusepiercingmouthpartstosuckoutplantjuices.Damageonleavesandstemslookslikeunevendiscoloredspotsaroundahole.Youngplantsmaywilt,turnbrown,anddie.Matureplantsmaysurvivebutgrowthisslowed.Damageonfruitssuchassquash,tomatoesandokraappearsasdarkholessurroundedbybumps,pits,orwhite-yellowishspots.Thelighterspotsdonotripentothesamecolorastherestofthefruit.Fruitsmayalsodimpleorgrowinstrangeshapes.Iden4fyingHarlequinBugsandS4nkBugsAdults5nkbugsareabouthalfaninchlongandshield-shaped.Theircolorsrangefromdarkbrown,tan,togreen.TheHarlequinbugisblackwithorange,yellowandredmarkings.Nymphsaresimilartoadultsbutsmallerandwithamoreroundedshape.Eggsarebarrel-shaped.Eggsarelaidingroupsonstemsandtheundersidesofleaves,andmaybeyellow,green,pink,orgray.[photoorillustra5on]Itisimportanttonotethatnotalls5nkbugsarepests.Somepredatorys5nkbugs,suchasthespinedsoldierbug,actuallyaOackothergardenpests.Theyshouldbeencouragedinthegarden.Thespinedsoldierbuglookssimilartoabrowns5nkbug,buthasspikesstandingoutonitsshoulders.

Adultharlequinbug.Photocredit:ClemsonUniversity-USDACoopera5veExtension

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Harlequinbugeggs.Photocredit:WhitneyCranshaw,ColoradoStateUniversity

LifeCycleS5nkbugadultsspendthewinterinoldplantsandothergardenliOer.Theycomeoutintheearlyspringtobeginlayingeggs.Inearlyspringeggstakeupto20daystohatch,butastheweatherwarmstheymayhatchinasfewas5days.Nymphsmatureintoadultsin5–8weeks.Popula5onstendtogrowthroughtheseason,geZngheaviestduringearlytomidfall.Therearetwotofourgenera5onsperyearinNorthCarolina,dependingonthespecies.Preven4on1)Growhealthyorganicplants.Strongplantscanhandlesomedamagefroms5nkbugsbeOerthanweak,strugglingplants.MakesurethatyourcropsaregeZngenoughsunlightandwater.Ensurethatthesoiliswell-drained,andrichinnutrientsandorganicmaOer.2)Growresistantvarie4es.SometypesofbrassicaplantsarenaturallyresistanttoHarlequinbugs.NCCoopera5veExtensionrecommends:Cabbage:CopenhagenMarket86,Headstart,SavoyPerfectDrumhead,Stein’sFlatDutch,EarlyJerseyWakefield.Collards:GreenGlaze.Cauliflower:EarlySnowballX,SnowballY.Radishes:RedDevil,WhiteIcicle,Globemaster,CherryBelle,Champion,RedPrince.3)Tillinlatefall.Tillingcroplecoversintothesoiloncecoldweatherhasarrivedcanreducethenumberofadults5nkbugswhosurvivethewinter.Thenfewercomebackoutthefollowingspring.4)Controlweedsinthegardenarea.S5nkbugsareaOractedbyweedyareasinornearthegarden.Weedsshouldnotbeallowedtospreadinthegarden.Weedyareasaroundthegardenshouldbemowedbeforespringplan5ngandregularlyacerthattokeeps5nkbugsfromhangingaround.5)Userowcovers.Keeps5nkbugsfromfindingyourcropbycoveringyourbrassicaplantswithalightweight“floa5ng”rowcoversuchasReemay.Thesematerials(asopposedtoplas5corheavierfabrics)letwaterandairthroughanddonotblockverymuchsunlight.Theycanbefoundatgardensupplystoresororderedfromseedcatalogs.Thecoverscanliedirectlyontheplants(theplantswilllicthecoverastheygrow),oryoucansupportthecoverswithwirehoops.Thetrickistokeeptheedgesofthecovers5ghtlyburiedorweightedsothatthes5nkbugscannotgetin.

Harlequinbugnymphanddamage.Photocredit:WhitneyCranshaw,ColoradoStateUniversity

Greens4nkbug.Photocredit:FrankPeairs,ColoradoStateUniversity

GeLngRidofHarlequinBugsandS4nkBugsWithoutToxicChemicals1)Scoutandhandpick.Scoutandhandpick.Handpickings5nkbugadults,nymphsandeggsearlyintheseasoncanreallyhelpyoucontrolthemlaterintheyear.Likewise,handpickinginthefallcancutdownthenumberofadults5nkbugsthatcomebackthefollowingseason.Scoutthegardenocenthroughouttheyear.Whenyoufinds5nkbugadults,nymphs,oreggclusters,crushthemwithyourfingers.Or,sinces5nkbugsreallydos5nkwhenyousquishthem,itmightbelesssmellytodropthemintoapailofsoapywater.2)Plantatrapcrop.Atrapcropisoneplantedtolurethes5nkbugawayfromyourmaincrop.Forinstance,ifyouhavehadaproblemwithHarlequinbugsonyourspringcabbage,nextyearplantmustardontheedgeofthegardenearlyintheseasontoluretheadultsastheycomeout.Later,killthe“trap”mustardcropalongwiththepestsbysealingthemalltogetherintoplas5cgarbagebagsandleavingtheminthesuntobakeforafewdays.Then,plantyourcabbageinanotherpartofthegarden.Butbeware–s5nkbugscanmovefast,somakesurethatyoudon’tjustscarethemoutofthetrapcropandintoanotherpartofthegarden!3)APractnaturalenemies.S5nkbugshavemanynaturalpredatorswhocanbeinvitedtohangaroundthegarden.WildflowersandherbswillaOractparasi5cfliesandwasps.Predatorssuchasbirds,toads,spiders,andprayingman5seswillmaketheirhomesinperennialherbandflowerbedsandsmallshrubsnearthegarden.4)Releasepredators.Minutepiratebugseats5nkbugeggsandnymphs,andprayingman5sescanaOackadults.Thesecanbeboughtandreleasedintothegarden.Lookforthemingardensupplycatalogs.5)Organicallyacceptableinsec4cides.Asalastresort,youmightchoosetoapplyleast-toxicinsec5cidesthatappearontheOrganicMaterialsReviewIns5tute’slistofproductsapprovedforCer5fiedOrganicfarms,suchasrotenone,pyrethrin,Neemoil,orinsec5cidalsoap.

Eventhoughthesespraysareapprovedfororganicfarms,theycanbehazardous,sobesuretofollowinstruc5onsonthelabelsverycarefully.Keepinmind,too,thattheseinsec5cidescankillpollinatorsandother“goodbugs”youwanttokeepinyourgarden.UseasliOleaspossible,andsprayonlyintheearlymorningorlateeveningwhenthe“goodbugs”arelessac5ve.Insec5cidalsoapcanburntheleavesofyourplants,sodonotspraythemindirectsunlightorwhentemperaturesareabove80°.Insec5cidesareusuallyonlyeffec5veinslowingsquashbugsdown,notstoppingthem.Spraysareusuallyonlyeffec5veinslowings5nkbugsdown,notstoppingthem.Adults5nkbugsandtheireggsareveryresistanttosprays.Sprayingshouldbedonesoonacerthefirsteggshatchandthenymphshavecomeout.Thespraysmustcomeintocontactwiththenymphstowork,sotrytocoverthewholeplant.Weeklyspraysmaybeneededsincenews5nkbugshatchallseasonlong.Obviously,even“organic”sprayscomewithrisksandproblems,sotrytheother5psherefirst,andyoumaybeabletoskipthespraysaltogether.

Greens4nkbugnymph.Photocredit:ClemsonUniversity-USDACoopera5ve

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Spinedsoldierbug(i.e.thegoodguys–notethebigpointyshoulderpads!)

Photocredit:FrankPeairs,ColoradoStateUniversity

Thisfactsheetwaswri-enwiththeneedsofnon-commercialhome,schoolandcommunitygardenersinmind.Cer:fiedOrganicgrowers,orthoseseekingacer:fica:on,shouldcheckwiththeircer:fyingagencybeforeusingANYinsec:cide.Someorganicallyacceptableinsec:cidesareapprovedforuseinCer:fiedOrganicsystemsonlyagainstcertainpestsorincertainsitua:ons.

SourcesEllis,BarbaraandBradley,FernMarshall,editors.TheOrganicGardener'sHandbookofNaturalInsectandDiseaseControl:ACompleteProblem-SolvingGuidetoKeepingYourGardenandYardHealthyWithoutChemicals.RodalePress,1996.Flint,MaryLouise.PestsoftheGardenandSmallFarm:AGrower'sGuidetoUsingLessPes5cide,2ndEdi5on.UniversityofCaliforniaPress,1998.“HarlequinBugs.”InsectandRelatedPestsofVegetables.CenterforIntegratedPestManagement,NorthCarolinaStateUniversity,NCCoopera5veExtensionService.ViewedMarch,2012:[link]Bambara,StephenandCasey,Chris5ne.“NoRomanceinHarlequinBugInfesta5on.”NorthCarolinaPestNews,NorthCarolinaStateUniversityCollegeofAgriculture&LifeSciences,DepartmentsofEntomologyandPlantPathology,NCCoopera5veExtensionService.Volume19,Number17,August6,2004.ViewedMarch,2012:[link]“S5nkBugs.”CenterforIntegratedPestManagement,NorthCarolinaStateUniversity,NCCoopera5veExtensionService.ViewedMarch,2012:[link]Ipsan,AnneOe.2010.“HowtoManageS5nkBugs.”UniversityofMarylandExtension–WashingtonCounty.ViewedMarch,2012:[link]