the sugarcane aphid: management guidelines for grain and...

TheSugarcaneAphid:ManagementGuidelinesforGrainandForageSorghuminTexas.AllenKnutson,RobertBowling,MichaelBrewer,EdBynum,andPatPorterTexasA&MAgriLifeExtensionandResearch,TexasA&MUniversity

Introduction.Thesugarcaneaphid(SCA)hasrecentlybecomeoneofthemostimportantinsectpestsofgrainandforagesorghuminTexasandthesouthernUS.ThesugarcaneaphidoriginallyfedonlyonsugarcaneintheUS.In2013,itwasfoundfeedingonsorghumnearBeaumont,TX.Thissorghum-feedingbiotypeofthesugarcaneaphidresultedfromeitherageneticchangeintheexistingUSpopulationoranewintroductionintotheUS.In2013,thesugarcaneaphidinfestedsorghumintheRioGrandeValley,TexasGulfCoastandinnorthTexasandinsouthernOklahoma,LouisianaandMississippi.Sugarcaneaphidssurvivedthe2013-2014winterinsouthTexasandduringthespringandsummerof2014,dispersedthroughoutmuchofTexasand12southernstates.In2015,thesugarcaneaphidagaindispersedthroughTexasintoOklahomaandKansasandthesoutheasternUS,eventuallyinfesting17statesrepresenting90%oftheUSsorghumacreage.Thispestcanbeeconomicallycontrolled,butgrowersmustfrequentlyassessinfestationstoproperlytimeaninsecticide,ifneeded,topreventcroplossandharvestdifficultiesduetohoneydewaccumulation.Sorghumhybridswithresistancetosugarcaneaphidarebeingdevelopedandwillplayanimportantpartinmanagingsugarcaneaphid.Resistanthybrids,alongwithselectiveinsecticidesandbiologicalcontrolprovidedbybeneficialinsects,areimportantcomponentsofanintegratedpestmanagementprogramforsugarcaneaphid.Identification.Sugarcaneaphidsarepaleyellow,grayortan.Thecorniclesor“tailpipes”,feetandantennaeareblack.TheSCAfeedsontheundersideofsorghumleaves.Initialcoloniesconsistofonlyafewaphidsbutcanincreasesuchthataphidcoloniescovermuchofthelowerleafsurface.Oncethesorghumheademerges,SCAcanalsobefoundinthegrainhead.Theydonotfeedontheupperleafsurface.Theyareoftenfoundincompactcoloniesduringinitialinfestation,butlargepopulationscandevelopwithinafewweekscoveringmuchoftheleafsurface.Sugarcaneaphidsproducelargeamountsofhoneydewwhichcollectonleaves,leavingthemstickyandshiny.Whenfirstlookingforaphids,theshinyreflectionofhoneydewonleavescanhelpdetectsmallcoloniesThegreenbugisanothercommonaphidthatfeedsontheundersideofsorghumleaves.Ithasadarkgreenstripedownitsback,unlikethesugarcaneaphid.Thecornleafaphidisalsofoundinsorghumbutitisadarkgreencolor,feedsinthewhorlofthesorghumplantandisrarelyapest.Theyellowsugarcaneaphidalsofeedsonsorghum.Itisbrightyellowwithrowsofdarkspotsandshortcornicles,butitdoesnotproducehoneydew.SeeFigure1.LifeCycle.AllSCAarefemalesandgivebirthtoliveyoung.Immatureaphidsmaturetoadultsinaboutfivedaysandliveforabout4weeks.Aphidnumberscanincreaseveryrapidlyduringthesummer.AtCorpusChristi,aninfestationof50SCAperleafincreasedto500perleafin2weeks.Forthisreason,onceSCAarefoundinafield,itshouldbemonitored1-2timesaweektodetermineifinfestationsexceedthetreatmentthresholdatwhichtimeaninsecticideapplicationshouldbeconsideredtopreventcroploss.Underwarmdryconditionsthatareoptimalforaphidreproduction,twiceaweekfieldscoutingishighlyadvisable.SugarcaneaphidsneedlivingsorghumorJohnsongrass,plantstosurvivethewinter.SmallcoloniesofSCAcanbefoundonJohnsongrassandvolunteersorghumwhichremaingreenthroughoutthewinterin

theRioGrandeValleyandGulfCoastofTexasandinnorthernMexico.LittleisknownabouttheabilityofSCAtooverwinterinnorthernareasofTX.In2015,smallcolonieswerefoundonJohnsongrassinearlyAprilnearWacoandHillsboro,suggestingthatSCAcanoverwinterasfarnorthascentralTexasinsomeyears.AsSCAcoloniesbecomecrowdedand/orfoodqualitydeclines,adultswithwingsbegintoappear.Althoughweakfliers,wingedaphidscanbecarriedonthewindacrosslongdistances.ItisbelievedthateachspringwingedSCAaphidsarecarriedbywindsfromoverwinteringsitesinMexicoandsouthTexastonorthernareasofTexasandthenfromfieldtofieldduringthegrowingseason..HostPlants.Sugarcaneaphidsareknowntofeedandreproducewellongrainandforagesorghum(Sudangrass,sorghum/Sudanhybrids,foragesorghum,shattercane)andJohnsongrass.AllofthesehostsareinthegenusSorghum.LaboratorytestsshowthatSCAdoesnotsurviveonwheat,oats,oronseedlingfoxtailmilletorprosomillet.HybridpearlmilletisnotaspeciesofSorghum.However,smallcoloniesofSCAaresometimespresentbutlittledamageresults,thushybridpearlmilletisconsideredapoorhostofSCA.WingedSCAaphidsmaybefoundonothercrops,suchascorn,buttheyeitherfailtoestablishcoloniesoronlysmallcoloniesdevelopwhichsoondieoutwithoutcropdamage.ThesugarcaneaphidalsofeedsonsugarcaneintheRioGrandeValley,butpopulationsusuallydonotincreasetothelargenumbersobservedinsorghum.Damage.Sugarcaneaphidsfeedbysuckingplantsap,butthereisnoevidenceofitinjectingatoxin.Feedingcausesleavestoturnyellow,purpleandfinallybrownasleaftissuedies.Infestationsonpre-bootsorghumcanresultinsignificantgrainloss,butinfestationspresentduringgraindevelopmentcanalsoreduceyields.Largeinfestationscanstuntgrowthandresultinunevenpanicleemergencefromtheboot.Thestickyleavesandstalksclogcombinesatharvestandreduceseparationofthegrainfromtheplants.Combinesmayrequireservicetimetowashoffthehoneydewandremovestalksandgrainheads.Infestationsinforagesorghumsalsokillleaves,slowgrowthandreduceforageyields.Honeydewcontaminatingleavesandstemscanalsogumupcutterbarsandmachineryatharvest.Honeydewiscomposedprimarilyofplantsugarsandwaterandeventuallydriestoaharmlessresidue,butablacksootymoldoftengrowsonthehoneydewonleaves.Thisblackmoldinhibitslightabsorptionneededforphotosynthesisandmayreducetheeffectivenessofinsecticidesandharvestaidchemicals.SorghumstressedbySCAfeedingmaybemoresusceptibletostalkrotsandlodgingfrequentlyoccursfollowingheavyplantdamageduetoaphidfeeding.SamplingSCAInfestationsinGrainSorghum.Beginlookingforsugarcaneaphidswhenplantsareinthe4-5leafstageinsouthTexasandthe8-10leafstageinmorenorthernareasofthestate.Mildwintersmayincreasethepotentialforearlierinfestations.The“FirstDetection”samplingplandetailedbelowisdesignedtodetermineifsugarcaneaphidsarepresentinthefieldandthereforethefieldisatrisk.Thissamplingdoesnotrequirecountingaphids.IfSCAaphidsarefoundinthefield,thenitisnecessarytobeginthesecondsamplingprotocoltodetermineiftheinfestationhasreachedtheactionthresholdatwhichtimeaninsecticideshouldbeappliedtoprotectcropyield.FirstDetection:IstheFieldatRisk?

1. Onceaweek,examineplantsalong50feetofrow,dividingthesamplingeffortbetweenthefieldedgeandatleast25feetintothefield.

2. Ifhoneydewispresent,lookforsugarcaneaphidsontheundersideofaleafabovethehoneydew.

3. Inspecttheundersideofleavesfromtheupperandlowercanopyfrom15-20plantsperlocation.

4. SampleeachsideofthefieldaswellassitesnearJohnsongrassandtallmutantplants.5. Checkatleast4locationsperfieldforatotalof60-80plants.6. Ifnosugarcaneaphidsarepresent,oronlyafewwinglessorwingedaphidsareonupperleaves,

thencontinueonceaweekscouting.Ifsugarcaneaphidsarefoundonlowerormid-canopyleaves,begintwiceaweekscouting.Useoneofthetwothresholdsbelowtodetermineifaphiddensitiesexceedatreatmentthreshold.MakingATreatmentDecision.Twoactionthresholds,theSouth-CentralTexasEconomicThresholdandtheTexasHighPlainsGrainSorghumActionThreshold,arepresentedbelowtoaidindeterminingwhenaninsecticidetreatmentisneededtoprotectyield.

South-CentralTexasEconomicThreshold

TheSouth-CentralTexaseconomicthresholdisbaseduponthenumberofaphidsperleafduringthepre-bootandbootstageandhasbeensuccessfullyusedinsouthandcentralTX.FieldSamplingProtocol.Oncesugarcaneaphidsarefoundinafield,usethefollowingprotocoltoassesstheinfestation.

1. Examinetheundersideofonecompletelygreenleaffromthelowercanopyandtheuppermostleaf(orleafbelowflagleafatboottoheading)andestimateandrecordthenumberofSCAperleafa.

2. Examine2leavesfromeachof5randomlyselectedplants(10leaves)perlocation.3. Repeatat4locationsforatotalof40leavesperfield.4. Calculatetheaveragenumberofaphidsperleafforthefield(totalaphidscounted/totalleaves

inspected).

aCountingexactnumbersofaphidsperleafisimpractical,andanaphidestimationtoolhasbeendeveloped,‘ScoutingSugarcaneAphid’andcanbefoundathttp://ccag.tamu.edu/sorghum-insect-pests/underQuickInformationSheetsandGuides.

EconomicThreshold1.Ifthefieldaverageis50-125sugarcaneaphids/leaforgreater,applyaninsecticidewithin4daysandevaluatecontrolafter3-4days(refertoinsecticidelabelsforre-entryintervals).ContinuetomonitorSCAinfestationsuntilharvesttodetermineifasecondinsecticideapplicationisnecessary.2.Considertreatmentat50aphids/leafiflimitedtoonlyonceaweekscoutingoriftheweatheriswarmanddry.3.Ifthefieldaverageislessthanthethresholdlevel,continuescoutingtwiceaweek. Theeconomicthresholdof50-125aphids/leafisbaseduponthepotentialyieldlossifsugarcaneaphidisnotcontrolled,thecostofcontrolandtheexpectedmarketvalueofthecrop.Economicthresholdsfordifferentcostsforcontrol(insecticideandapplicationcost)andmarketvalueareshowninthetablebelow.Asanexample,ifthecostofcontrolis$20/acreandthemarketvalueis$5.00/bushel,thenthetreatmentthresholdisanaverageof90ormoreSCA/leaf.

Theeconomicthresholdcanalsobeeasilydeterminedusingtheon-lineSugarcaneAphidTreatmentDecisionToolforGrainSorghumat:http://bitly.com/scasorghumTable.Economicthresholdsforsugarcaneaphidinfestationsstartingatorbeforebootstageofdevelopmentingrainsorghum.Aninsecticidetreatmentshouldbeconsideredwhentheaveragenumberofsugarcaneaphidsperleafexceedsthevalueinthetable.Marketvalueofcrop CostofControl=

$15/acreCostofControl=

$20/acreCostofControl=

$25/acre$3.50/bushel,$6.25/cwt 100 130 165$5.00/bushel,$8.93/cwt 70 90 115$6.50/bushel,$11.60/cwt 55 70 90

Thesevaluesareapplicabletograinsorghumandinfestationsstartingatorbeforebootstageofdevelopment.Infestationsoccurringduringgrainfillarelessdamagingthanearlierseasoninfestations,butmaygreatlyreduceharvestefficiencyduetohoneydewcontamination.Atthistime,lateseasonmovementtotheheadanddetectionofhoneydewintheheadarebestindicatorsoftheneedtoapplyaninsecticide.

TexasHighPlainsActionThreshold

TheTexasHighPlainsActionthresholdusesbothaphidcountsandpercentofplantsinfestedwithSCAtomakeatreatmentdecision,varieswithcropdevelopmentandwasusedsuccessfullyin2015inwestTexaswhereSCAinfestationsdevelopatorsoonafterbloomstageandintothelatergrowthstages.FieldSamplingProtocol.FieldSamplingProtocol.Oncesugarcaneaphidsarefoundinafield,usethefollowingprotocoltoassesstheinfestation.

1.Walk25feetintothefieldandliftupandexaminetheundersideofgreenleavesfromthelowercanopytotheuppermostleafforpresenceofaphidsonaplant.Watchforhoneydewthatindicatesaphidsontheleafabove.

2.Keeparecordofthenumberofplantsinfestedwithanyaphidsandnumberofplantsnotinfestedwithaphids.

3.Examineaminimumof10plantsat4locationsacrossthefield.Calculatethepercentageofplantsinfested(dividethenumberofplantswithanyaphidsbythetotalnumberofplantsexaminedandmultiplyby100).

4.Ifgrainsorghumisinthebootorflowering–milkgrowthstagealsomakeanestimateofthenumberofaphidsperleaf.Atthesegrowthstagesitiscriticaltotreatbeforeaphidnumbersreachlevelsabove100perleaf.

WestTexasGrainSorghumActionThreshold

GrowthStage

Decisionthresholdspecifictothesugarcaneaphid

Pre-Boot 20%ofplantswithpresenceofaphids

Boot 20%ofplantsinfestedwith50aphidsperleaf

Flowering-Milk 30%ofplantsinfestedwith50aphidsperleaf

SoftDough 30%ofplantsinfestedandlocalizedareaswithheavyhoneydewandestablishedcolonies

Dough 30%ofplantsinfestedandlocalizedareaswithheavyhoneydewandestablishedcolonies

BlackLayer Heavyhoneydewandestablishedaphidcolonies.Onlytreattopreventharvestproblems.Observepreharvestintervals

ThisthresholdwasrevisedfromathresholdoriginallyfromMississippiStateUniversity.

ControlOptionsAfter1stApplication.

• Checkfieldsforcontrolafter4to7days.

• Ifpoorcontrolandaphidcoloniesof50ormore/leafarestillpresentanotherapplicationiswarranted.

• Iftherewasgoodcontroloftheaphidcontinuescoutingfields2Xperweekforre-infestationorarapidincreaseinaphidnumbers.

• ForwhorltoearlydoughgrowthstagestheGrainSorghumActionThresholdintheabovetablemaystillbeusedtodeterminetheneedforadditionalinsecticideapplications.

• Fromdoughtolatedoughgrowthstages,asecondapplicationmayberequiredwhenaphidsarere-establishing,40%-50%ofthetotalleafareahasaphiddamage,andpredatorpopulationsarenotsuppressingaphidpopulations.

• Atblacklayergrowthstagethroughharvestanapplicationmayberequiredtopreventharvestproblems.

Insecticides.Sivanto200SL(BayerCropScience)insecticidehasaSection2(ee)labelforuseongrainandforagesorghumtocontrolsugarcaneaphid.BayerCropSciencehasappliedtoEPAfora24clabeltoreducethegrainsorghumPHIfrom21daysto14days,socheckcurrentlabel.ASection18Emergency

ExemptionlabelfortheuseofTransformWG(DowAgroSciences)forcontrolofsugarcaneinsorghumhasbeensubmittedtoEPAbutasofthiswritingEPAhasnotruledonthisrequest.Goodcoverageisnecessaryforeffectivecontrol.Applicationratesof5gallons/acrebyairor10gallons/acrebygroundarerecommended.Informationbelowisforeducationalpurposes.Readandfollowlabeldirections. Sivanto200SL TransformWGUseRateforSugarcaneAphid 4-7oz/acre Minimumintervalbetweenapplications

7days

Minimumapplicationvolume 10GPAbyground2GPAbyair

Maximumrateperyear 28ozperacre Pre-harvestinterval 21daysfordriedgrainorstraw

orstover.7daysforgrazing,forage,fodderorhayharvest

Restrictedentry 4hours Chlorpyrifos(Lorsban®,Nufos®),dimethoateandmalathionarealsolabeledforaphidcontrolinsorghum.AlthoughtheseproductsprovidesomecontrolofSCA,universitytrialsdemonstratethattheseproductsarenotaseffectiveasSivanto.ManagingSugarcaneAphidsDuringGrainFillandPriortoHarvest.Althoughsugarcaneaphidinfestationspresentafterheademergencemayhavelessimpactonyield,theseinfestationscancontinuetoproducelargequantitiesofhoneydewwhichcaninterferewithharvest.Raincanhelpwashhoneydewfromleaves.Insecticidescanbeappliedatthistimebuttheiruseislimitedbytheirpre-harvestrestrictions(seeTablefordaysafterapplicationbeforeharvestispermitted).HarvestaidchemicalssuchasglyphosateandsodiumchloratehavebeenusedtokillsorghumleavesandthereforereduceSCAinfestationspriortoharvest.Unfortunately,ifplantsareslowtodesiccate,SCAmayhavetimetomoveupintothesorghumheadwheretheycontinuetofeedandproducehoneydew.Forthisreason,highratesofharvestaidsthatkillleavesquicklymaybenecessary.Readandfollowlabeldirectionsfortheseproducts.SeedTreatments.Insecticideseedtreatmentsprovidecontrolofaphids,includingSCA,andsomeotherearlyseasoninsectsforabout4-5weeksafterplanting.TheirvalueforcontrolofSCAwilldependonhowsoonafterplantingtheSCAinfeststhefield.ManagingSCAInfestationsinForageSorghum.Sugarcaneaphidcancauseextensivedamagetoforagesorghums,sudangrass,sorghum/sudanhybrids,shattercaneandJohnsongrassmeadows.Aphidinfestationscankillleaves,increasestalklodgingandhoneydewcontaminationcanplugharvestmachinery.TreatmentthresholdsforSCAinfestingforagesorghumsandJohnsongrassmeadowshavenotbeendetermined.Untilthosethresholdsareavailable,thethresholdslistedaboveforgrainsorghumcanprovideaguidetomakingtreatmentdecisions.ForagesorghumfieldsshouldbemonitoredasdescribedaboveatleastweeklyforSCA.ControlofSCAwithinsecticidesrequiresgoodcoverageoftheentirecanopy,includinglowerleaves,whichmaybedifficulttoachieveinforagesorghumduetothedensecanopyandespeciallyifthecropistall.Forthisreason,earlyharvestorgrazingmaybethebestoptionifgoodinsecticidecoveragecannotbeachieved.Ifasecondcuttingisdesired,thefieldshould

againbescoutedonceaweektodetermineifSCAre-infestthefieldafterharvest.IfSCAarefound,thefieldshouldagainbescoutedtwiceperweektodetermineifaninsecticideisneededtoprotectyield.BeneficialInsects.Syrphidflylarvae,ladybeetles,greenandbrownlacewings,andparasiticwaspsfeedonsugarcaneaphidandcanhelpsuppresstheincreaseofSCAinfestations.Adultsyrphidfliesaresmall,about¼-1/2inchlongandbrightlycoloredyellowandblack,resemblingabee.Theyaresometimescalledhoverfliesbecauseoftheirhoveringflight.Whiletheadultflyonlyfeedsonnectarandhoneydew,themaggot-likelarvaestagefeedsonaphids.Thelarvaisagreen,brownorgrayslug-likemaggotwithnolegsandatinyheadatthesmallendofthetaperedbody.Larvaemoveslowlyamongtheaphidcolony,suckingthejuicefromaphids.TheadultandlarvalstagesofseveralspeciesofladybeetlesalsofeedonSCAinsorghum.Severalspeciesofparasiticwaspsalsoattacksugarcaneaphid.Thesetinywaspsdeposittheireggintothesugarcaneaphidandtheegghatchesintoalarvathatfeedsonandsoonkillsthehostaphid.Oncethelarvahascompleteddevelopmenttotheadultstage,theadultwaspemergesfromthedeadaphid.Aphidskilledbyparasitesarecalledmummies.ParasitismbytheAphelinuswaspresultsinblackorblue-backmummies.Whiletheseparasiticwaspsaretinyanddifficulttoseeinthefield,thepresenceofaphidmummiesisevidenceoftheirimpact.Anotherparasiticwasp,Lysiphlebustestaceipes,attacksgreenbugsandcornleafaphidsinsorghumandwheatandresultsinabrownmummy.However,mostsugarcaneaphidsareprotectedfromattackbyLysiphlebusduetoaninternalbacteriumthatpreventstheimmatureparasitoidfromdeveloping.SorghumHybridsResistanttoSCA.ResearchstudiesandfieldobservationshaveshownthatsomecommercialsorghumvarietiesexhibitlessleafdamageorhostfewerSCAaphidsthanotherhybrids.Resistanthybridshavegenesthatprovidesomelevelofprotectionfromrapidpopulationincrease(antibiosis)ordamage(tolerance)bysugarcaneaphid,therebypreservingyieldpotentialofthecrop.Resistanceisarelativetermandhybridsmaybedescribedassusceptible,moderatelyresistantorresistant.ResistanceisnotimmunityandSCAwillbepresentonresistanthybridsandaninsecticidetreatmentwillbenecessaryifinfestationsexceedthetreatmentthreshold.Resistancecanbeexpressedastoleranceorantibiosis.Whenresistantisexpressedastolerance,thehybridcanwithstandorrecoverfrominsectdamagethatwouldresultinyieldlossinasusceptiblehybrid.Whenresistanceisexpressedasantibiosis,theinsectcannotsurviveorreproduceaswellasonasusceptiblehybrid,andthusfeweraphidsarepresentontheresistanthybrid.HybridswithsomeresistancetoSCA,sometimesreferredas“tolerant”hybrids,maydelayaninfestationfromreachingthetreatmentthreshold,thusprovidingmoretimeforbeneficialinsectstohaveanimpact.However,thesehybridsmustbefrequentlyscoutedtoassessSCAinfestationlevelsasdescribedabove.Onestrategytousethescoutingprocessdescribedabovetomonitortheaphidpopulation,andiftheinfestationreachesthethresholdlevel,considerplantdamageindeterminingtheneedforaninsecticidetreatment.. BreedinglinesofsorghumwithhighlevelsofresistancetoSCAhavebeenidentified,butseveralyearswillbenecessarytomovethisgeneticresistanceintocommercialhybrids.SeedcompanieshaveidentifiedhybridswithsomeresistancetoSCA,andalistofthesehybridsisavailablefromtheNationalSorghumProducersat: http://sorghumcheckoff.com/pest-management/.AskyourseeddealerabouttheavailabilityofgrainsorghumhybridswithresistancetoSCA.ManagingSorghumMidge,HeadwormsandStinkbugsWhenSugarcaneAphidisPresent.TheinsecticidesTransformandSivantoareeffectiveagainstSCAbutarenotlabeledforcontrolofmidge,headwormsorstinkbugsinsorghum.Manyinsecticideslabeledforcontrolofthesepestsaretoxictobeneficialinsects,includingladybeetles,syrphidflies,andparasiticwaspswhichfeedon

sugarcaneaphids,whichhelpreducetherateofincreaseofsugarcaneaphidpopulations.Itisthereforeimportanttopreservebeneficialinsectswheneverpossible.Considerthefollowingwhenselectinginsecticidestocontrolmidge,headwormsandstinkbugswhensugarcaneaphidsarealsopresentinthefield.1.Midge,headwormsandstinkbugs,whenpresentattreatmentthresholds,areacertainthreattoyieldandprofitability.WhilethereissomeriskofSCAoutbreaksfollowinguseofsomeinsecticides,cropyieldshouldnotbejeopardizedinanefforttoprotectnaturalenemies.2.Formidgeandstinkbugcontrol,therearenolabeledoptionsthatwillnotreducethenumbersofbeneficialinsects(seeTable).Ifaninsecticideisappliedforcontrolofmidgeorstinkbugs,monitorsugarcaneaphidsfrequentlyandbepreparedtomakeanapplicationofSivantoifsugarcaneaphidnumbersexceedthetreatmentthreshold.3.Forheadworm(cornearwormandfallarmyworm)control,thepyrethroidinsecticides(Group3and3aintablebelow),methomylandchlorpyrifos,arebroadspectruminsecticidesandaretoxictomostnaturalenemies(seeTable).Incomparison,PrevathonandBeltarelesstoxictonaturalenemiesandveryeffectiveoncaterpillarpestsincludingcornearwormandfallarmyworm.Besiegeisapre-mixofthesameactiveingredientasPrevathonplusapyrethroid,andhencewillnotbeassafeonbeneficialinsectsasPrevathonalone.Spinosad,theactiveingredientinBlackhawk,ismuchlesstoxictomanynaturalenemiesthantheseotherinsecticides.Useofhigherratesandlongresidualinsecticidesextendthetimebeforenaturalenemiescanre-populateafield.4.Scoutfieldsandbasedecisionstoapplyaninsecticideonpestcountsofmidge,headwormsandstinkbugs.Thatis,donotdecidetotreatbasedsolelyoncropgrowthstageortimeofyear.5.Theeconomicthresholddependsonthecurrentvalueofthecrop,thenumberofgrainheadsperacreandthecostofcontrol.Thesevariablescanbeenteredintocalculatorsavailableon-linetodeterminethenumberofmidge,headwormsorricestinkbugsthatshouldbecontrolledtoavoidcroplossgreaterthanthecostoftheinsecticideapplication.Thesecalculatorsareavailableat:https://insects.tamu.edu/extension/apps/index.htmlInsecticidesLabeledforControlofMidge,Headworm(CornEarworm,FallArmyworm)andStinkbugsinSorghum.ActiveIngredient

BrandName

Group

LabeledforControlof: RelativeImpactonAphidNaturalEnemies2

Daystowaitafterapplicationbeforeharvest

Midge

HeadWorm1

Stinkbugs

cyfluthrin Baythroid,Tombstone

3a Yes Yes Yes High 14

esfenvalerate AsanaXL 3 Yes Yes No High 21lambdacyhalothrin

KarateZ,Warrior,Lambda-Cy

3 Yes Yes Yes High 30

zeta-cypermethrin

MustangMax

3 Yes Yes Yes High 14

gamma-cyhalothrin

Declare 3 Yes Yes Yes High 30

alpha-cypermethrin

Fastac 3 Yes Yes Yes High 14

chlorpyrifos Lorsban,Nufos

1B Yes Yes No High 30(1pt)60(>1pt)

methomyl Lannate 1a Yes Yes No High 14dimethoate Dimethoate

4001b Yes No No High 28

spinosad Blackhawk 5 No Yes No Low 21flubendiamide Belt 28 No Yes No Low 14chlorantraniliprole Prevathon 28 No Yes No Low 1lambda-cyhalothrinpluschlorantraniliprole

Besiege 3and28

Yes Yes Yes High 30

1Headwormsincludecornearwormandfallarmyworm.PyrethroidsareoftenineffectiveonlargerFAW2Dataonimpactonaphidnaturalenemiesisoftenlacking.Ratingmaybebasedonimpactonhoneybeeonly.3Groupsrefertoinsecticideswithsimilarmodesofaction.Asexamples,Group3consistsofpyrethroidinsecticideswhileorganophosphateinsecticidesareGroup1.Rotatingbetweengroupsisanimportantmethodofslowingthedevelopmentofpestswithresistancetoinsecticides. AdditionalResources:http://txscan.blogspot.com.SignuptoreceivecurrentinformationonSCAprovidedbyTexasAgriLifeExtensionEntomologycanbeaccessedat:TexasSugarcaneAphidNews:hhttp://ccag.tamu.edu/entomology/.AwebsiteforresearchandExtensioninformationonsugarcaneaphidinsouthTexas.textensioninformationonSCAinSouthTexas.Acknowledgements:ResearchoneconomicthresholdsusedinsouthandcentralTexaswasgeneratedfromseveraltestlocationsalongtheTexasGulfCoastandalsoLouisianaasprovidedbyDavidKerns,LouisianaStateUniversity.InformationalsoprovidedbymembersoftheTexasA&MAgriLifeSugarcaneAphidTaskForce,USDA-ARSandotherstateuniversities.

Theinformationgivenhereinisforeducationalpurposesonly.ReferencetocommercialproductsortradenamesismadewiththeunderstandingthatnodiscriminationisintendedandnoendorsementbyTexasA&MAgriLifeExtensionisimplied.

Feb,2016

Afewofthephotostobeconsidered.

(Photo:Dr.JourdanBell,TexasA&MAgriLifeExtension)

Figure1.Aphididentification.SameasFigure2inpublicationNTO-035

Thereareabout50SCAaphidsontheleafbelow