Weed Management in Texas Cotton - Texas A&M Universitypublications.tamu.edu/COTTON/Cotton Weed...
Transcript of Weed Management in Texas Cotton - Texas A&M Universitypublications.tamu.edu/COTTON/Cotton Weed...
WeedManagementinTexasCotton
SCS-2016-16
WeedManagementinTexasCotton
JoshuaMcGinty,Ph.D-AssistantProfessorandExtensionAgronomist,CorpusChristi,TX
EmiKimura,Ph.D.-AssistantProfessorandExtensionAgronomist,Vernon,TXPaulBaumann,Ph.D.-ProfessorandStateExtensionWeedControlSpecialist,CollegeStation,TX
PeteDotray,Ph.D.-ProfessorandExtensionWeedControlSpecialist,Lubbock,TXGaylonMorgan,Ph.D.-ProfessorandExtensionCottonSpecialist,CollegeStation,TX
Contents
GENERALPRACTICES....................................................................................................................................2
HERBICIDERESISTANCE...............................................................................................................................2
Table1.Mechanismofactionofherbicideslabelledforuseincotton.......................................................4
CULTURALCONTROL...................................................................................................................................5
PREPLANTBURNDOWN...............................................................................................................................7
WEEDMANAGEMENTATPLANTING...........................................................................................................7
POSTEMERGENCEWEEDCONTROL.............................................................................................................7
POST-HARVESTWEEDMANAGEMENT........................................................................................................8
Table2.Preplantburndownherbicideoptions...........................................................................................9
Table3.Preplant-incorporatedherbicideoptions....................................................................................13
Table4.Preemergenceherbicideoptions.................................................................................................15
Table5.Postemergenceover-the-topherbicideoptions..........................................................................18
Table6.Post-directedorhoodedherbicideoptions.................................................................................22
Table7.Wickorwiperappliedherbicideoptions.....................................................................................26
PHOTOGRAPHSOFCOMMONWEEDS......................................................................................................27
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GENERALPRACTICES
Akeycomponentinsuccessfulcottonproductionistheeffectivemanagementofweeds.Thecottonplantisnotparticularlycompetitivewithmanyweedspecies,especiallyearlyintheseason.Researchhasshownthatevenlightinfestationsofweedsduringthisperiodoftimecansignificantlyimpactcottonyields.Weedscanalsocreatedifficultiesduringharvestandnegativelyimpactlintqualityduetostainingandincreasedforeignmaterialinthelint.Thispublicationdescribeskeypointstoconsiderwhenmanagingweedsincottonaswellascurrentrecommendationsforcontrol.
HERBICIDERESISTANCE
Herbicideresistantweedsarenaturallyoccurringbiotypesofaspecieswiththeinheritedabilitytosurviveandreproducedespiteexposuretoaherbicidethatpreviouslywaseffectiveforcontrollingthespecies.Thetermbiotypedescribesplantswithinaweedspeciesthatmaylookexactlyalikebuthavebiologicaltraitsuncommontothepopulationasawhole.Thedevelopmentofresistanceisacceleratedwhenweedcontrolmeasuresrelyheavilyuponchemicalcontrolandwithoutincludingcultural,mechanical,andbiologicalweedcontrolmeasures.Therearecurrently246species(143dicotsand103monocots)ofherbicideresistantweedsglobally(Heep,2015).Ofwhich,herbicideresistantweedsidentifiedinTexasincludeperennialryegrass(ALSinhibitors),barnyardgrass(PSIIinhibitor),Palmeramaranth(PSIIinhibitorsandEPSPsynthaseinhibitors),kochia(ALSinhibitors),johnsongrass(ALSinhibitors),andtallorcommonwaterhemp(EPSPsynthaseinhibitors)(Heap,2015).Oftheseherbicideresistantweedcases,theglyphosateresistantAmaranthusspp.(Palmeramaranthandcommonwaterhemp)arethemosttroublesomeinTexascottonduetothewidespreadrelianceuponglyphosatealoneforweedmanagement.Theseweedsarecapableofproducinginexcessof500,000seedperfemaleplantandcanspreadrapidlythroughoutaregiononceestablished.Belowareafewkeypointstoconsiderformanagingtheseherbicideresistantweeds.
PreventionandManagementofResistantWeedsa. Diversifycropproductionpractices
Croprotationisoneofthemostsignificantcomponentsofeffectiveweedmanagementincotton.Inadditiontohelpingwithnematodeanddiseasemanagement,croprotationsallowtheuseofadditionalherbicidemechanismsofaction.
b. CultivationOnceamainstayofweedmanagementincotton,cultivationhasdeclinedsignificantlywiththecommercializationofglyphosateandglufosinatetolerantcottonvarieties.However,withtheriseofglyphosateresistantweedsincottonproduction,cultivationisonceagainaviableweedmanagementtoolinmanyoperations.
c. Usetherecommendedrate,timingofapplication,andsprayvolume.Whenapplyinganyherbicide,besuretousethefulllabeledrateofthatproductandapplyatthepropertime.Manypostemergenceherbicidesareonlyeffectivewhenappliedtoverysmallweeds.Ifappliedtoolateorattoolowanapplicationrate,weedescapescanbeexpected.Theefficacyofnon-systemicherbicides,suchasglufosinate(Liberty),ishighlydependentuponobtainingthoroughspraycoverageasisstatedontheproductlabel.Goodspraycoverageisachievedbyapplyingtherecommendedcarriervolumeandusingtheappropriatespraynozzle.
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d. AvoidusingasinglemechanismofactioninyourherbicideprogramHerbicidemechanismofactiondescribesthewaythataherbicidecontrolssusceptibleweedspecies.Currently,thereare12herbicidemechanismsofactionavailableforuseincotton(Table1).Itisimportanttotargetproblematicweedspecieswithatleasttwodifferentmechanismsofaction,andtochangeherbicideprogramsfromyeartoyear(Figure1).TheWeedScienceSocietyofAmerica(WSSA)hasdevisedanumberingsystemforclassifyingherbicidemechanismsofactionintogroups.Often,thesegroupnumberscanbefoundonproductlabels.AllherbiciderecommendationsinthispublicationwillincludetheWSSAgroupnumber(s)foreachherbicide.UseoftheWSSAnumberingsystemshouldbeasimplerapproachforunderstandingtheherbicidemechanismofaction.
Figure1.Exampleofthesustainabilityofutilizingmultipleherbicidesitesofactionandrotatingthesefromseasontoseason(adaptedandmodifiedfromwssa.net).
Season1:Group9
Season2:Group9
Season3:Group9
Season1:Group9and4
Season2:Group9and14
Season3:Group1and2
SustainableMinimizesresistantweed
evolution
NotSustainableAcceleratestheevolution
ofresistantweeds
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Table1.MechanismofactionofherbicideslabelledforuseincottonMechanismofAction WSSAGroup# Representativeproducts
ACCaseinhibitors 1 AssureII,FusiladeDX,PoastPlus,SelectMax
ALSinhibitors 2 Envoke,Express,FirstShot,Harmony,LeadOff,Staple
Microtubuleassemblyinhibitors 3 Prowl,TreflanSyntheticauxins 4 2,4-D,Clarity
PhotosystemIIinhibitors5 Caparol,7 Cotoran,Direx,Karmex,Linex
EPSPsynthaseinhibitors 9 Roundup(glyphosate)Glutaminesynthetaseinhibitors 10 Liberty
Carotenoidbiosynthesisinhibitors12 BrakeFX13 Command
PPGoxidaseinhibitors 14 Aim,Cobra,ET,Goal,Reflex,Resource,Sharpen,Valor
VLCFAinhibitors 15 DualMagnum,Warrant,Zidua,Outlook
Unknown 17 MSMAPhotosystemIinhibitors 22 GramoxoneSL
e. Keeprecordsofweedpopulationsandherbicideapplication
Goodrecordkeepinghelpstoplananeffectivepreventionprogramforherbicideresistantweeds.Italsohelpstoavoidusingthesameherbicidemechanismofactioneachyear.Ifaherbicideprogramfailedtocontrolaweedorweeds,thatprogramshouldbeavoidedinthefieldwherethefailure(s)wereobserved.Repeatedapplicationsofthesameherbicidewillonlyservetoincreaseherbicideresistantweeds.
f. ScoutherbicidefailuresfollowingsprayingWeedswhichsurviveaherbicideapplicationmaybetheresultofapplicationerrorsandarenotnecessarilyresistantweeds.Herbicidefailurecanbecausedbypoorspraycoverage,incorrecttimingofapplications,“washing-off”ofpostemergenceherbicidesbyrainfall,oradverseenvironmentalconditionssuchaspoorsoilmoisture,lowhumidity,orextremetemperatures.Whenweedcontrolfailuresoccur,checktoseeifspatialpatternsexistinthefield.Ifsurvivingweedsarepresentin“streaks”acrossthefield,thismaybetheresultofanapplicationerror.Ifthedistributionofsurvivingweedsisscatteredor“patchy”,thismayindicatethepresenceofaherbicideresistantbiotype.Ifresistantweedsaresuspected,itcanbeconfirmedbycollectingseedsofthesuspectedresistantweedsandhavingalegitimatescreeningtrialconductedonthemtodetermineresistance.Afew“redflags”ofherbicideresistantweedsare:(1)ifthesameherbicidehasbeenrepeatedlyappliedinthesamefield,(2)thesameweedspeciesarerepeatedlyfoundsurvivinginthesamelocationofthefield,and(3)ifdead(susceptible)plantscanbefoundatthesamelocationasthesurvivingweedsandthesedeadplantswereatthesamestageofgrowthatapplication.
Formanagementstrategiesforglyphosateresistantpigweeds,pleaserefertotheAgriLifeExtensionpublication,‘4-stepProgramforManagingGlyphosateResistantPigweedsinTexasCotton’.
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CULTURALCONTROLFieldSelection
Growthofcottonseedlingsisslowbecauseoftheperennialnatureofcotton,whichdevotesmuchofitsenergyintorootdevelopmentratherthanshootgrowth.Thefirst10weeksafterplantingisthecriticaltimeofweedmanagementuntilcottonseedlingsbecomecompetitiveagainstweeds(BuchananandBurns,1970).Weedmanagementbecomeseasierifacleanfieldwithlittleweedinfestationisselected.Itisimportanttoknowthefieldcharacteristicssuchassoiltestresults,fertility,insect/diseasemanagementhistory,andweedpopulationandinfestationlevel.Understandingthefieldcharacteristicsimprovesefficacyandefficiencyofweedmanagementprograms.Prevention
Weedmanagementshouldbeconductednotonlywithinthefield,butalsoaroundthefields,ditchbanks,andfencelines.Theweedsaroundthefieldcanproduceprolificamountsofseedsandspreadtheinfestationintothefield.Italsoprovidesrefugeforinsects,diseases,andnematodes.Itisimportanttothoroughlycleanequipmentandclothestopreventthetransportofweedseedsintootherfields,especiallyinthecaseofpigweed(orcarelessweed).SeedbedPreparation
Itisbeneficialtotakeadvantageofrainorapplyirrigationtoallowforweedgerminationbeforeseedbedpreparation.Seedbedpreparationshouldbeconductedaftercontrollingtheweedseedlings.Cottonrequiresamoistandfirmseedbedwithgoodseed-to-soilcontact.Properseedbedpreparationallowscottonseedstogerminaterapidly,resultinguniformseedlingemergence.Auniformcottonstandismorecompetitiveagainstweedinfestation.RowDirection
Rowdirectioncaninfluencetheamountofsunlightavailabletoweeds.Whenrowsarearrangedinanorth-southdirection,theremaybegreatershadingofthemiddles.However,importanceshouldbeplacedontheotherpreventativemeasuresasrowdirectionisdependentuponothermanagementfactors,suchastheavailablelengthofrow,slopes,andequipment.RowSpacing
Canopyclosureoccursearlierwithnarrowerrows(<15in)andsolidplantingascomparedtowiderrows(>40in)andskiprowpatterns.Narrowerrowspacingprovideshigherweedsuppressionascomparedtothewiderrowspacingduetothegreatercanopycoverage;however,narrowrowspacingrequiresmoreresourcessuchassoilmoistureandnutrientsthanwiderowspacing.Rowspacingshouldbeproperlyadjustedtotheavailableresourcestoensuremaximumplantgrowthandproduction.QualitySeed
Useofweed-freeseedsisessentialtoreduceintroductionofnewweedspeciesandweedinfestationintheplantingrow.Highqualityseedsalsoprovideadvantagessuchasseedlingdiseaseresistance,highgerminationpercentage,reducedriskforreplanting,rapidanduniformseedlingemergence,andeasierdecisionmakingforweed,insect,anddiseasecontrol.Alltheseadvantageshelptoproduceacompetitivecottonstandagainstweedinfestation.
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VarietySelectionUnlikewheatseeds,cottonseedscannotbesavedforthefollowingyearsduetothepatented
herbicidetolerantandinsectprotectiontraitsofrecentcottonvarietiesunlessconventionalseedsareused.Over90%ofTexascottonproducerspurchasecertifiedseedseachyearwithsingleanddoublestackedherbicidetoleranttraits.Itiscriticalthatproducersknowproblematicweedsintheirfieldssothattheappropriateherbicidetolerantvarietiesmaybeselected.PlantingDate
Cottonplantingisbestdeterminedbysoiltemperaturesinceadequatesoilandairtemperatureimprovesgrowthrateandseedlingvigor,producingacompetitivecottonstandagainstweedinfestations.Favorablesoilconditionsforcottonseedgerminationincludehighsoiloxygenconcentration,adequatesoilmoisture,andsoiltemperaturesabove64°F(BomanandLemon,2005).Optimumplantingdatecanbedeterminedbymeasuringthesoiltemperatureat8-inchdeptheverydayuntilthe10-dayaveragetemperaturebecomes65°F.Cottonplantedearlywithlowsoiltemperatureextendsthegrowingseason;however,thisalsoincreasesriskofstandestablishmentfailurebyslowgrowth,weakseedlingvigor,andweakcompetitivenessagainstweeds.SeedingRate
Plantedseedsandseedlingsareexposedtoasevereenvironment,whereoftenonlyafractionofplantedseedwillbecomematureplants(Gwathmeyetal.,2010).Cottonplantedattoolowaseedingrateincreasestheriskfornon-uniformorthinstands,resultinginyieldlossandreducedharvestefficiency.Cottonplantedattoohighaseedingrateincreasescompetitionamongcottonplantsforwater,nutrients,andsunlight,resultinginlowseedlingvigor.Properseedingrateadjustedtothefieldconditionproducesavigorousanduniformstand.Goodseedlingestablishmentiscriticalforsuccessfulweedmanagement. CropRotation
Croprotationwillhelpreducetargetweedpopulationsgradually.Eachcrophasitsownplantingandgrowingwindows,life-cycle,rootingdepth,leaforientation,andnutrientandmoisturerequirements.Thesecultural,biological,andseasonaldifferencesmodifythefavorableconditionsforweedscreatedundercontinuouscottonproduction,thusnegativelyinfluencingthegrowthandreproductionofsomeweedspecies.Croprotationalsoallowsforrotatingherbicidestotargetproblematicweedspecies.Inaddition,croprotationhasbeenobservedtohaveapositiveeffectonlintyield.Cottonlintyieldwas18to44%higherinthecotton-sorghumrotationsystemthanthecontinuouscottonsystemwhenevaluatedatHalfway,Texas.Thepositiveeffectoftherotationonlintyieldwasevenmorepronouncedinthewaterstressedenvironmentofan8-yearstudyconductedbyTexasAgriLifeResearch(Bordovskyetal.,2011).FieldScouting
Pre-,mid-,andpost-seasonfieldscoutingishighlyrecommendedtokeeprecordsofweedspeciesandinfestationlevel.RefertoapublicationpreparedbyTexasA&MAgriLifeExtension,WeedIdentification:UsingPlantStructuresasaKey,forhelpwhenscoutingfieldsforproblematicweeds.
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PREPLANTBURNDOWN
Akeycomponenttoeffectiveweedmanagementistostartwithacleanfield.Thiscanbeachievedbynormaltillageoperationsandherbicideincorporationsinconventionallytilledfields,orthroughtheuseofpreplantburndownherbicides.Manyherbicideoptionsareavailableforcontrollingemergedweedspriortoplantingaswellasprovidingresidualcontrolofweedsuntilplanting.Alwaysbeawareofplantback(croprotation)restrictionstoavoidcropdamage.RefertoTable2forcurrentrecommendationsforpreplantburndownherbicides.
WEEDMANAGEMENTATPLANTING
Often,themostcompetitiveweedsarethosethatemergebeforeoratthesametimeasthecrop.Thisisparticularlytrueincotton,whichtendstohaveaslowergrowthrateasaseedlingascomparedtoothercrops.Theseearly-seasonweedsareveryeffectiveatcompetingforthesameconsumableresourcessuchaswater,nutrients,andsunlightthatthecottonseedlingneedsforhealthygrowth.Iftheseweedsarenotcontrolled,significantyieldlossescanbeexpected.Witheffectiveearlyseasonweedcontrol,theyieldpotentialofthecropisprotected.Thus,itisimportanttoapplyresidualherbicides(herbicideswithsoilactivity)justpriorto,oratplanting.Theseherbicideswillcontrolweedsbeforetheyemerge,reducingtheneedforpostemergenceherbicideslaterintheseason.Itisimportanttonotethatrainfall,irrigation,ormechanicalincorporationisneededwiththeseresidualherbicidestomovethemintothesoilandactivatethem.RefertoTables3and4forrecommendationsforpreplantincorporated(PPI)andpreemergence(PRE)herbicides.
POSTEMERGENCEWEEDCONTROL
Weedsthatemergeduringtheseasonmustbecontrolledeitherbycultivationorchemicalmeans.Severalherbicideoptionsexistforpostemergence(POST)weedcontrol.WhenapplyingPOSTherbicides,itisvitaltoapplythematthepropertiming,asmanyPOSTherbicideswillonlybeeffectiveifappliedtoverysmallweeds.Thisisespeciallytrueforthepigweedsorcarelessweeds.InadditiontoPOSTherbicides,therearemanyherbicidesavailableforover-the-topordirectedsprayapplicationsthatwillprovideresidualcontrolofweeds.Postdirectedapplicationstakeadvantageoftheeffectivenessofaparticularherbicideonweedsthatmightbeinjurioustothecrop.Directionalorhoodedsprayapplicationsaccomplishthispracticeinadditiontoprovidingresidualcontrol,dependingontheherbicide.Ideally,POSTherbicideswillbeappliedinatankmixwitharesidualpartnertocontrolemergedweedsaswellastoprovideextendedresidualcontrol.Foremergedgrassweeds,severalhighlyeffectivecontroloptionsexistwiththegraminicide(grass-specificherbicides)suchasAssure,Fusilade,Poast,andSelect.Whenapplyingthesegrass-specificherbicides,avoidtankmixtureswithLiberty280SL,whichhavebeenshowntoresultinreducedgrasscontrol.Additionally,tankmixesofthegrassherbicidesandStapleorEnvokeshouldalsobeavoided.RefertoTables5,6,and7forcurrentrecommendationsforpostemergenceover-the-top,post-directed,hooded,andwickorwiperappliedherbicides.
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POST-HARVESTWEEDMANAGEMENT
Afterharvest,therecanbeasubstantialamountoftimeleftforweedgrowthanddevelopmentbeforetemperaturesdroptoalevelunfavorableforwarmseasonweedgrowth,particularlyinsouthTexas.Thus,weedcontrolstrategiesmustbeimplementedtopreventtheproductionofadditionalweedseedthatwillbecomeproblemsduringthenextseason.Inconventionallytilledfields,tillageoperationsprovidegoodcontrolofemergedannualweeds;howeverthisdisturbancealsobringsnewseedsuptothesoilsurface.Intheabsenceoftillage,herbicidesmustbeusedforweedcontrol.Similartochemicalweedmanagementstrategiesduringthegrowingseason,herbicideprogramsafterharvestshouldincludebothpostemergenceandpreemergenceherbicidestocontrolweedsalreadypresentandprovideresidualweedcontrollaterintotheyear.Inaddition,thepost-harvestperiodprovidesanexcellentopportunitytoreducepopulationsofperennialweedsthatmightbepresentatthistime.Applicationofpostemergencesystemicherbicidesatthistimecangreatlyenhancetranslocationoftheherbicidetotherootsystemofperennialplants,improvingchancesfortheirelimination.Whenchoosingaresidualherbicidetoapplyafterharvest,paycloseattentiontoanyplant-backrestrictionsontheproductlabel.
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Table2.Preplantburndownherbicideoptions
WeedsControlledProduct,Rate/A,ActiveIngredient
Group#
TimetoApply Notes
Selectedbroadleafweeds,refertolabel
AimECupto2.0floz(carfentrazone-ethyl)
14Postemergencetoweeds,priortoplanting
Forbestperformance,applytoactivelygrowingweedslessthan4inchestallorrosetteslessthan3inchesindiameter.Maybetankmixedwithglyphosate,glufosinate,paraquat,2,4-D,ordicamba.
Henbit,seedlingdockCaparol4L1.2–1.6pt(prometryn)
5
Fallorwinter,preemergenceorpostemergencetosmallweeds
UseinGulfCoastandBlacklandsonly.Forbestresults,applybeforeweedemergence.Ifhenbithasemergedbutislessthan4to6inchestall,addasurfactantoremulsifiableoil.Forwinterweedcontrolonly;additionalherbicideswillbeneededforspringandsummerweedcontrol.
Annualandperennialbroadleafweeds
Clarity8.0floz(dicamba)
4
Fallorwinterwhenweedsare2–4leafstageandrosettesarelessthan2in.across
Donotapplyinregionsthataveragelessthan25in.precipitationannually.Plantcottononlyafteraminimumof1inchofrainfalloroverheadirrigationand21daysafterapplication.
Manyannualgrassandbroadleafweeds,refertolabelforweed-specificrates
Direx4L0.8–1.6qt(diuron)
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Preemergenceorpostemergencetoweedslessthan2intall,15to45dayspriortoplanting
Ifapplyingtoemergedweeds,addanonionicsurfactant.Completeanyplannedtillagepriortoapplication,astillageoperationsimmediatelyafterapplicationmaycausecropinjury.
Horseweed,henbit,shepherd’spurse
Envoke0.10oz(trifloxysulfuron)
2 Earlypreplant
CurrentlylabelledinTexasonlyforareaseastofI-35forpreplantuses.Forotherregions,refertothelabelforspecificrestrictions.Applyaloneorintankmixturesforresidualcontrolorsuppression,atleast90dayspriortoplantingcotton.
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Table2continued.preplantburndownherbicideoptions
Selectedbroadleafweeds,refertolabel
ETX0.3–1.25floz(pyraflufenethyl)
14Postemergencetoweeds,priortoplanting
Applyinaminimumof10gallonswater/Abygroundand5gallonswater/Aaerially.Forbetterresults,add1.0to2.0%cropoilconcentratetospraysolution.UsethehigherCOCrateforlargerlabelledweedsorinlowmoistureconditions.
AnnualbroadleafweedsExpress0.25oz(tribenuron)
2Postemergencetoweeds,priortoplanting
Applywhenthemajorityofweedshaveemergedandareactivelygrowing.Allow14daysafterapplicationbeforeplantingcotton.Stressfulconditionsmayweakencottonandresultincropinjury.
Manygrassandbroadleafweeds
FlexstarGT3.0–4.5pt(fomesafen+glyphosate)
14,9Postemergencetoweeds,priortoplanting
OnlylabelledforuseinTexasforareaseastofU.S.Highway77andnorthofStateRoad239,includingallofCalhounCounty.Donotapplytomediumorfinetexturedsoilsascropinjurymayoccur.Moistureisrequiredtoactivatethisherbicideforresidualactivity.
Annualbroadleafweeds
FirstShotSG0.5–0.8oz(thifensulfuron-methyl+tribenuron-methyl)
2Postemergencetoweeds,priortoplanting
Allow14daysafterapplicationbeforeplantingcotton.Onlighttexturedsoils,allow21daysbeforeplanting.Maybetank-mixedwithotherherbicidestocontroladditionalweeds.
Manyspecies,refertolabel
Glyphosateproductsratesvary;refertolabel(glyphosate)
9Postemergencetoweeds,priortoplanting
Allowatleast2weeksafterapplicationbeforetillage.Whereglyphosateresistantweedsarepresent,addatankmixpartnertocontrolemergedweedsandprovideresidualcontrol.Neverstore,mix,orsprayingalvanizedorunlinedsteeltanks(exceptstainlesssteel).
Selectedbroadleafweeds,refertolabel
Goal2XL1.0–2.0pt(oxyfluorfen)
14Preemergenceorpostemergencetoweeds
Someresidualcontrolmaybeexpected.Applytoweedseedlingsnotexceedingfourtrueleaves.Fallowbedsshouldbeworkedthoroughlytoaminimumdepthof2.5inchesbeforeplanting.Donotapplywithin7daysofplanting
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Table2continued.Preplantburndownherbicideoptions
Emergedannualweedsandtopkillsuppressionofperennials
GramoxoneSL2.5–4.0pt(paraquat)
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Postemergencetoweeds1to6inchestall,priortoplanting
Beforeplanting,preparelandtoallowmaximumweedandgrassemergencebeforetreatment.Plantwithminimalsoildisturbance.Noresidualcontrolwiththisherbicide.Applyinatleast10galwater/Abygroundplus1.0qtnonionicsurfactantper100galspraysolutionor1galcropoilconcentrateper100galspraysolution.Atlowersprayvolumes,useadriftcontrolorspraydepositionadjuvant.Checklabelfortankmixoptions.
AnnualbroadleafweedsHarmony0.3–0.5oz(thifensulfuron)
2Postemergencetoweeds,priortoplanting
Maybetankmixedwith2,4-Dorglyphosateherbicidesforincreasedcontrol.Allowatleast7daysafterapplicationbeforeplantingcotton,tankmixtureswithotherherbicidesmayincreasethetimeneededbeforeplanting.Stressfulconditionsmayweakencottonandresultincropinjury.
Manyannualbroadleafweeds,refertolabel
LeadOff1.5–2.0oz(thifensulfuron-methyl+rimsulfuron)
2
Preemergenceorpostemergencetoweeds,priortoplanting
For1.5ozrate,allowatleast30daysbeforeplantingcotton.Forratesof1.5to2.0oz,allow60daysbeforeplanting.Addanonionicsurfactanttospraymixture.Multipletankmixpartnersareavailable,refertolabelformoreinformation.
Manyannualbroadleafandgrassweeds;refertolabel
Liberty280SL22–43floz(glufosinate)
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Postemergencetoweedsinfallowfields,post-harvest,beforeplanting,orbeforeemergenceofcotton
Spraycoverageiscriticalforperformance,applyinatleast15galwater/Abygroundor10galwater/Aaerially.Seasontotalapplicationsmaynotexceed72or87floz/A,dependingoninitialapplicationrate.Makeapplicationsbetweendawnand2hoursbeforesunsetwithwarm,humidconditionsforimprovedperformance.Makesequentialapplications10to14daysapartasneeded.
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Table2continued.Preplantburndownherbicideoptions
AnnualbroadleafweedsResource2.0–4.0floz(flumiclorac)
14Postemergencetoweeds,priortocottonemergence
Applytoactivelygrowingweedsattheproperstagesofgrowthasindicatedintheproductlabel.Maybecombinedwith2,4-Dorglyphosateherbicides.Applywith1qt/Acropoilconcentrateormethylatedseedoil.Mosteffectivewhenappliedundersunnyconditionsandtemperaturesabove70oF.
Annualandperennialbroadleafandgrassweeds,aswellassedges;refertolabel
Sequence2.0–3.5pt(glyphosate+S-metolachlor)
9,15Postemergencetoweeds
Donotapplytosandorloamysandsoils.Maximumof2.5pt/Aonsandysoilsand3.5pt/Aonmediumandfinesoils.Ifheavyrainfalloccursimmediatelyafterplanting,cropinjurymayoccur,especiallywherepoordrainageoccursortheseedslithasnotbeenproperlyclosed.
Selectedbroadleafweeds,refertolabel
Sharpen1.0floz(saflufenacil)
14Postemergencetoactivelygrowingweeds
Formaximumefficacy,usetherecommendedadjuvants,includingMSO+AMSorMSO+UAN.Allow42daysafterapplicationbeforeplantingcotton.Inareaswithlessthan25inchesofannualrainfall,allow42daysbeforeplantingand1inofrainfallorirrigation.Donotapplytosandysoilswithlessthan1.5%organicmatter.CommonlyusedasatankmixpartnerwithglyphosatetobroadenweedspectruminWestTexas.
Annualandperennialbroadleafweeds
2,4-D(6lbai/gal)0.66to2.66pt(2,4-D)
4Postemergencetoweeds,priortoplanting
Allowatleast30daysafterapplicationandatleast1inrainfallorirrigationwithina24-hrperiodbeforeplantingcotton.
Selectedweeds,seelabel
ValorSX,Rowel2.0–4.0oz(fallburndown)1.0–2.0oz(springburndown)(flumioxazin)
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Preemergenceorpostemergencetoweeds,priortoplanting.
Ifweedsareemerged,includeatankmixpartner.Inconventionaltillage,allowatleast30daysand1inchrainfalloroverheadirrigationbetweenapplicationandplanting.Instrip-tillorno-till,allowatleast14daysand1inchofrainfallorirrigationbetweenapplicationandplanting.Includeacropoilconcentrateormethylatedseedoilwithspraysolution.
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Table3.Preplant-incorporatedherbicideoptions
WeedsControlledProduct,Rate/A,ActiveIngredient
Group#
TimetoApply Notes
Manyannualgrassesandsmall-seededbroadleafweeds
Prowl3.3EC1.2–4.8pt(pendimethalin)
3
Immediatelybeforeplantingorupto140dayspriortoplanting
Incorporateassoonaspossibleandnolaterthan7daysafterapplication.Forincorporation,useanimplementcapableofuniformincorporation1to2inchesdeep.Two-passincorporationwillgivemoreconsistentresults.
Manyannualgrassesandsmall-seededbroadleafweeds
ProwlH2O1.0–4.0pt(pendimethalin)
3Upto60daysbeforeplanting
Incorporateuniformlyintotheupper1to2inchesofthesoilbyrainfall,sprinklerirrigation,ormechanicalincorporation.Two-passincorporationwillgivemoreconsistentresults.Donotapplytosoilswithmorethan3%organicmatter.
Manyannualgrassesandsmall-seededbroadleafweeds
Treflan(4lbai/gal)1.0–2.5pt(trifluralin)
3AnytimefromOct15untilplanting
Incorporatewithadoubledisk,powerincorporator,fieldcultivator,rollingcultivator,orbedconditioner.Thefirstincorporationshouldoccurwithin24hoursafterapplication.Makeasecondpasswithgrounddrivenequipment.Rollingcultivatorsandbedconditionersshouldonlybeusedoncoursetomediumtexturedsoils.Groundmaybeleftflatorbeddedoverwinter.Iflandisleftflat,takecareduringspringbeddingoperationstopreventturningupuntreatedsoil.Donotapplyinthefalltosoilsthatarewet,inpoorcondition,orsubjecttoflooding.InBrazoria,Calhoun,Chambers,FortBend,Galveston,Harris,Jackson,Jefferson,Liberty,Matagorda,Orange,Waller,andWhartonCounties,ratesof1.5to3.0pt/Acanbeused.DonotuseonanycropgrowninPecosorReevescounties.
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Table3continued.Preplant-incorporatedherbicideoptions
Manyannualgrassesandsmall-seededbroadleafweeds
TreflanTR-105.0–12.5lb(conventionaltillage)5.0–20.0lb(conservationtillage)(trifluralin)
3Fallorspringuntilplanting
Two-passincorporationrequired,withthefirstpassoccurringwithin24hoursafterapplication.Forbetterresults,delaythesecondincorporationatleast5daysafterthefirstandrunequipmentinadifferentdirectionthanthefirstincorporation.DonotuseonanycropgrowninPecosorReevesCounties.
15
Table4.Preemergenceherbicideoptions
WeedsControlledProduct,Rate/A,ActiveIngredient
Group#
TimetoApply Notes
Manyannualgrassesandsmall-seededbroadleafweeds
BrakeFX(fluridone+fluometuron)
12,7 Preemergence
Donotuseonsandy,loamysand,orfinesandyloamsoilsinWestTexas.Donotapplymorethan2lbsoffluometuronperacrefromallsources.Donotapplymorethan42floz/AofBrakeFXperyear.Donotapplyinconjunctionwithorganophosphateinsecticides.
Manyannualbroadleafweedsandsomeannualgrasses,refertolabelforweed-specificrates
Caparol4L1.6–4.8pt(prometryn)
5 Preemergence
Donotuseonsandorloamysand.Rainfallorirrigationisrequiredafterapplicationtoobtaingoodweedcontrol.Avoidbroadcastapplicationstocottonplantedinfurrowsmorethan2indeep.Bandapplicationsshouldnotbewiderthanthebottomofthefurrows.Cottonmaybereplantedthroughtreatedsoil,butdonotre-applyproduct.Donotuseinglandlesscottonvarietiestoavoidcropinjury.
Annualgrassesandbroadleafweeds
Command1.33–2.66pt(clomazone)
13 Preemergence
Disulfotonorphorateorganophosphateinsecticidesmustbeappliedin-furrowwiththeseedatplantingwithatleast0.75lbaiasacropsafener,orcropinjurywilloccur.Injurymayoccuronsandysoils.Off-sitemovementofCommandcancausefoliarwhiteningofsomeplants.Avoidsprayingwithin300ftofdesirableplants
Manyannualgrassesandbroadleafweeds,refertolabelforweed-specificrates
Cotoran4L2.0–4.0pt(fluometuron
7
Preemergence,atplanting,orafterapreplantincorporatedapplicationofProwlorTreflan
Activitymaybedelayedorreducedduringdryweather.Donotplantcropsotherthancottonwithin6monthsofthelastapplication.Donotuseonsand,loamysand,orfinesandyloamsoilsnoroncottonplantedinfurrows.Donotfeedfoliagefromtreatedfieldsorgintrashtolivestock.Asuspensibilityagentmaybenecessary.
16
Table4continued.Preemergenceherbicideoptions
Manyannualgrassesandsomesmall-seededbroadleafweeds
DualMagnumorDualIIMagnum1.0–1.33pt(S-metolachlor)
15Preplantincorporatedorpreemergence
Donotapplytosandorloamysandsoils.Donotapplytofurrow-plantedcotton.Applypreemergenceorincorporatenomorethan1inchdeepbefore,at,orafterplanting.Plantcottonatleast1inchdeeponfinesoilsand1.5inchdeeponmediumorcoarsesoils.Forbestcontrolofyellownutsedge,applypreplantincorporated.DonotuseinGainescounty,TX.
Manyannualgrassandbroadleafweeds,refertolabelforweed-specificrates
Direx4L0.8–2.2qt(diuron)orKarmex80DF1.0–2.75lb(diuron)
7 Preemergence
Useonsandyloamorheaviersoils.Donotapplytosandorloamysandsoils.Cottonmaybereplantedthroughthetreatedband,orreworkbedsbeforereplanting.Donotuseonsoilscontaininglessthan1.0%organicmatter.Donotuseasapreplantorpreemergencetreatmentwheresoil-appliedorganophosphateinsecticidesareusedbecauseofthepotentialforseverecropinjury.
Manygrassandbroadleafweeds
FlexstarGT3.0–4.5pt(fomesafen+glyphosate)
9,14 Preemergence
OnlylabelledforuseinTexasforareaseastofU.S.Highway77andnorthofStateRoad239,includingallofCalhounCounty.Donotapplytomediumorfinetexturedsoilsascropinjurymayoccur.Moistureisrequiredtoactivatethisherbicideforresidualactivity.Theglyphosatecomponentofthisproductwillcontrolemergedweeds.
Annualgrassesandsmall-seededbroadleafweeds
ProwlH2O1.0–4.0pt(pendimethalin)
3 Preemergence Applyatplantingorupto2daysafterplanting
17
Table4continued.Preemergenceherbicideoptions
Annualbroadleafweeds,suppressionofsomeannualgrasses
Reflex1.0–1.5pt(fomesafen)
14 Preemergence
Applyonlytocoarsetexturedsoils,ascropinjurymayoccuronmediumandfinesoils.OnlylabelledforuseinTexasforareaseastofU.S.Highway77andnorthofStateRoad239,includingallofCalhounCounty.FIFRASection24(c)label:MaybeusedwestofHwy277fromWichitaFallstoAnson,andnorthofHwy180totheNMandOKstatelines.IncludesFisher,Scurry,Borden,andDawsoncounties.Apply1.0pt/Atooverheadbroadcastsprinklerirrigatedcottononly.Aminimumof13inchesofirrigationmustbeappliedthroughAugust31.Rotationalrestrictionsare15to24monthsforwheat,andmorethan36monthsforsorghum.
Grassesandsmall-seededbroadleafweeds
Sequence2.5–3.5pt(S-metolachlor+glyphosate)
9,15Preplantorpreemergence
Donotapplyonsandorloamysoils.Donotexceed2.5pt/Aonsandyloamsoils,or3.5pt/Aonmediumandfinesoils.DonotapplyinGainesCounty.Ifheavyrainfalloccurssoonafterapplication,cropinjurymayoccur,especiallywherewaterstandsorwheretheseedingslitwasnotproperlyclosed.
Selectedbroadleafweeds,seelabelforweed-specificrates
StapleLX1.3–2.1floz(pyrithiobac)
2 Preemergence
Donotapplytosandyorloamysandsoils.Canbecombinedwithdiuron,fluometuron,orprometrynforabroaderspectrumofweedcontrol,seethelabelformoreinformation.Donotapplypreemergenceaerially.
Manyannualgrassesandsomesmall-seededbroadleafweeds
Warrant1.25–2.0qt/A(acetochlor)
15 Preemergence
Seelabelforappropriateratebasedonsoiltexture.Broadcastapplyanddonotincorporate.Cropinjurymayoccurundercoolconditionsandsaturatedsoils.Donotexceed4qt/Afortheseason.
18
Table5.Postemergenceover-the-topherbicideoptions
WeedsControlledProduct,Rate/A,ActiveIngredient
Group#
TimetoApply Notes
Annualandperennialgrassesincludingbarnyardgrass,bermudagrass,largecrabgrass,johnsongrass,junglerice,andTexasmillet
AssureII5.0–12.0floz(quizalofop)
1Postemergencetoactivelygrowinggrasses
Applicationsmustincludeeither1%v/vcropoilconcentrateor0.25%v/vnonionicsurfactant.Donotcultivatetreatedgrasses7dayspriortoapplicationor7daysafterapplication.Donotapplywithin80daysofharvest.Useaminimumof10galwater/Aundernon-aridconditions,and15galwater/Aunderaridconditions.
SelectedannualbroadleafweedsincludingPalmeramaranth,commoncocklebur,Venicemallow,morningglory,lanceleafsage
Cotoran4L2.0–4.0pt(fluometuron)
7
Postemergencewhencottonisatleast3in.tallandweedsarelessthan2in.
Includeupto0.50%v/vsurfactanttoimproveactivity.Donotfeedfoliageorgintrashtolivestock.MaybecombinedwithMSMAorDSMAforenhancedweedcontroltocottonfrom3in.talltofirstbloom.WestTexas:Donotuseonsandy,loamysand,orfinesandyloamsoils.Donotuseonfurrow-plantedcotton.
Manygrassesandsmall-seededbroadleafweeds
DualIIMagnum1.0–1.33pt(S-metolachlor)
15Postemergencetocotton,beforeweedsemerge
Over-the-topapplicationsmustbemadenolaterthan100daysbeforeharvest.Willneedmechanicalincorporation,rainfall,oroverheadirrigationforactivation.DonotuseinGainesCounty,TX
Selectivecontrolofgrasses,sedges,andbroadleafweedsincludingPalmeramaranthandannualmorningglory(red,ivyleaf)
Envoke0.10–0.15oz(trifloxysulfuron)
2
Postemergencewhencottonhasreachedatleast5trueleaves
Donotapplywithin60daysofharvest.Forover-the-topapplications,donottankmixwithanyotherherbicide,fertilizer,oradditiveotherthanNISasunacceptablecropinjurymayoccur.RefertolabelforregionspecificrecommendationsforTexas.
19
Table5continued.Postemergenceover-the-topherbicideoptionsManyannualandperennialgrassweeds,includingbarnyardgrass,bermudagrass,largecrabgrass,johnsongrass,junglerice,andTexasmillet
FusiladeDX6.0–24floz(fluazifop)
1
Postemergencetoactivelygrowinggrasses,refertolabelforspecificsizerequirements
Donotapplymorethan48floz/Aperseason.Donotapplyafterbollset.Donotharvestwithin90daysofapplication.Donotcultivatefrom7daysbeforeto7daysafterapplication.Cultivation2to3weeksafterapplicationmayprovideenhancedgrasscontrol.
Manyannualandperennialgrassweeds,includingbarnyardgrass,bermudagrass,largecrabgrass,johnsongrass,junglerice,andTexasmillet
Fusion6.0–24.0floz(fluazifop+fenoxaprop)
1Postemergencetoactivelygrowinggrasses
ForareaseastofI-35,useratesof6.0–12floz.ForareaswestofI-35,ratesare8.0–24floz.Donotapplymorethan24floz/Aperseason.Donotapplytocottonafterbollset.Donotharvestwithin90daysofapplication.Formoreregion-specificinstructions,refertoproductlabel.
Manygrassesandbroadleafweeds
Liberty280SL22–43floz(glufosinate)
10
Postemergenceover-the-toptoglufosinate-tolerantcotton
Useonlyonglufosinate-tolerantcotton.Consultlabelforweed-specificratesandtankmixcombinations.Efficacyisincreasedwithactivelygrowingweeds.Applyinatotalsprayvolumeofatleast10gal/A,15to20gal/Amaybeneededwithdenseweed/cropcanopies.Ifasingleapplicationexceeds29floz/A,theseasonalusemaynotexceed72floz/A,otherwisetheseasonalmaximumis87floz/A.Theadditionofammoniumsulfatemayimproveweedcontrol.WestTexas:smallweeds,43floz/A,andfavorableenvironmentalconditionsarerecommended.
Manygrassesandbroadleafweeds
Glyphosateproductsratesvary,refertolabel(glyphosate
9Postemergencetoactivelygrowingweeds
Useonlyonglyphosate-tolerantcotton.Whereglyphosateresistantweedsarepresent,addatankmixpartnertocontrolemergedweedsandprovideresidualcontrol.Neverstore,mix,orsprayingalvanizedorunlinedsteeltanks(exceptstainlesssteel).
20
Table5continued.Postemergenceover-the-topherbicideoptions
Selectedgrasses,broadleafweeds,andsedges.Refertolabel
MSMA62.66pt(MSMA)
17
Postemergenceover-the-topwhencottonis3to6incheshighoruptoearlyfirstsquarestage
Oneapplicationof2poundsai/Aisallowedperseason,exceptwhensalvageoperationisneeded.Asecondapplicationof2poundsai/Aisallowedforsalvageoperations1to3weeksafterthefirstapplication.Donotfeedtreatedfoliagetolivestock.Someburningandreddishdiscolorationoffoliagemayoccur.
ManyannualgrassandbroadleafweedsincludingPalmeramaranthandcommonwaterhemp.Alsocontrolsriceflatsedgeandyellownutsedge.
OutlookUpto21floz(dimethenamid-P)
15
Postemergencetocottonfrom1sttrueleaftomid-bloom,beforeweedsemerge
Donotapplyoncoarsesoilsclassifiedassandwithlessthan3%organicmatter,andwheregroundwaterislessthan30feetdeep.Donotapplymorethan21floz.Nopreharvestinterval.Outlookmaycausetemporaryinjurytocottonifhighrainfallandsaturatedconditionsoccurduringearlyseedlingdevelopment.
Manyannualandperennialgrassweeds,includingbarnyardgrass,bermudagrass,largecrabgrass,johnsongrass,junglerice,andTexasmillet
Poast0.75–3.75pt(sethoxydim)
1Postemergencetoactivelygrowinggrasses
Donotapplymorethan11.25pt/Aperseason.Donotcultivatewithin5daysbeforeor7daysafterapplication.Cultivationnosoonerthan7daysafterapplicationmayimproveseason-longcontrol.Refertolabelforweed-specificuserates.
Annualgrassesandsmall-seededbroadleafweeds
ProwlH2O1.0–2.0pt(pendimethalin)
3Postemergencetocotton,beforeweedsemerge
Onlyapplyover-the-toptocottonbetweenthe4-and8-leafstagesofgrowth.Applicationsmaycausetemporaryinjurytocotton.Postemergenceapplicationswillbemosteffectivewhenrainfalloroverheadirrigationisreceivedafterapplication.Maybetankmixedwithglyphosateonglyphosate-tolerantcotton,andwithglufosinateonglufosinate-tolerantcotton.
Manyannualandperennialgrassweeds,includingbarnyardgrass,bermudagrass,largecrabgrass,johnsongrass,junglerice,andTexasmillet
Select2EC6.0–16.0floz(clethodim)orSelectMax9–32floz(clethodim)
1Postemergencetoactivelygrowinggrasses
Useacropoilconcentrateat1%v/v.DonotapplyabroadleafherbicidewithinonedayafterapplicationofSelectorreducedgrasscontrolmayresult.Donotcultivatetreatedgrasses7daysbeforeorafterapplication.
21
Table5continued.Postemergenceover-the-topherbicideoptions
Broadspectrumofannualandperennialweeds,preemergenceactivityongrassesandsmall-seededbroadleafweeds
Sequence2.5–2.75pt(glyphosate+S-metolachlor)
9,15Postemergenceupto10leafstage
Useonlyonglyphosate-tolerantcotton.Ifrainfallorirrigationisnotreceivedwithin7daysofapplication,residualcontrolmaybereduced.Donotexceed2.5pt/Aoncottonwithlessthan5leaves.Donotharvestwithin100daysofapplication.Donotincludeammoniumsulfate.DonotuseinGainesCounty.
ManyannualbroadleafweedsincludingPalmeramaranthandannualmorningglory,seelabelforweed-specificrates
StapleLX2.6–3.8floz(pyrithiobac)
2
Postemergencetomostweedswhentheyare1-2inchestall,refertolabel
Useanonionicsurfactantatarateof0.25–0.5%v/v,oracropoilconcentrateat1.0–2.0%v/v.ForareaswestofHighway83onsandorloamysandsoilswithlessthan1.0%organicmatter,limitapplicationstoonein-seasonapplicationofabandofnomorethanone-thirdtherowwidth.Ifreplantingcottonisnecessary,plantoutsidethetreatedband.
Preemergenceactivityonannualgrassesandsmall-seededbroadleafweeds
Warrant1.25–2.0qt(acetochlor)
15
Postemergencetocotton,beforeweedsemergeandcottonreachesfirstbloom
Optimumtimingandrateis2-to3-leafcottonpriortoweedemergenceat1.5qt/A.Foremergedweeds,addapostemergenceherbicide.Ifnorainfallorirrigationoccurswithin10days,shallowincorporationwillbenecessary.Donotmixwithfertilizer,asseverecropinjurymayoccur.
22
Table6.Post-directedorhoodedherbicideoptions
WeedsControlledProduct,Rate/A,ActiveIngredient
Group#
TimetoApply Notes
Commonlambsquarters,ivyleafandpittedmorningglory,redrootpigweed,velvetleaf,andcommonwaterhemp
AnthemFlex2.73–3.80floz(pyroxasulfone+carfentrazone)
14,15
Postemergenceasadirectedspraytocottonfrom6in.talltofirstbloom,orapplyatlayby.
Applytocommonwaterhemplessthan2in.tall,morninggloryupto3leaves,andlambsquartersupto3in.tall.Forotherlabelledweeds,applybeforetheyreach4in.inheight.Theuseofanadjuvantisrecommendedforconsistentcontrol.
Annualgrassesandbroadleafweedsincludingcocklebur,devil’sclaw,commonlambsquarters,morningglory,piemelon,andpigweeds
Caparol4L1.6–3.2pt(prometryn)
5
Postemergenceasadirectedspraywhencottonisatleast12in.tallandweedsarelessthan2in.tall
IntheHighPlains,1.6to2.4pt/Aissufficient.Donottreatcottonthatisstressedduetodrought,cultivatordamage,orfertilizerapplications.Whenapplyingtoemergedweeds,add2qtsurfactantper100galofspraysolution.DonotuseintheRioGrandeValley.
Manyannualbroadleafweeds,includingPalmeramaranth,devil’sclaw
Cobra12.5floz(lactofen)
14
Postemergencedirectedtocottonover6to8in.tall,orapplyatlayby.
Theadditionof2ptnonionicsurfactantor0.5to1.0ptcropoilconcentrateper100galofspraysolutionconsistentlyenhancedweedcontrol.Refertolabelforspecificapplicationinstructionsforindividualweedspecies.
Manyannualgrassesandbroadleafweeds,refertolabelforweed-specificrates
Direx4L0.4–0.6qt(diuron)orKarmex80DF0.25–0.5lb(diuron)
7
Postemergencedirectedaftercottonis6to12in.tall,asneededupto2applications
Sprayyoung,activelygrowingweedslessthan2in.tall.Providesresidualcontrolofmanyweeds.Addasurfactanttospraysolution.Seelabelforweedandratespecifics.
Selectedannualgrassesandbroadleafweedsincludingcocklebur,morningglory,pigweed,smellmelon
Envoke0.10–0.25oz(trifloxysulfuron)
2Postemergencedirectedtocottonover6in.tall
Addnonionicsurfactantat0.25%v/vorcropoilconcentrateat0.5to1.0%v/v.Donotharvestfor60daysafterapplication.RefertolabelforregionspecificrecommendationsforTexas.
23
Table6continued.Post-directedorhoodedherbicideoptions
Annualbroadleafweedsincludingcocklebur,lambsquarters,morningglory,pigweed
Fierce3oz(flumioxazin+pyroxasulfone)
14,15
Postemergencethroughhoodedorshieldedsprayersaftercottonis6in.tall,oratlaybyaftercottonis16in.tall.
Applytoactivelygrowingweedsattheproperstageofgrowthasindicatedonthelabel.MaybecombinedwithMSMA,diuron,orglyphosate.Mosteffectivewhenappliedundersunnyconditionsattemperaturesabove65oF.
Annualgrassesandbroadleafweedsincludingcocklebur,devil’sclaw,lambsquarters,morningglory,piemelon,pigweed
Goal2XL1.0–2.0pt(oxyfluorfen)
14Postemergencedirectedtocotton6to8in.tall
Foroptimalcontrol,apply2.0pt/Atoactivelygrowingweedswithnomorethan4trueleaves.Weedsatthe2to3leafstagecanusuallybecontrolledatthe1.0pt/Arate.Donotusehollowconenozzles.
Annualgrassesandbroadleafweedsincludingcocklebur,lambsquarters,pigweed,smellmelon
LaybyPro1.0–2.4pt(linuron+diuron)
7Postemergencedirectedtocottonatleast8in.tall
Forcotton8to15in.tall,applyratesof1.0to1.5pt/A.Forcottontallerthan15in.,ratesashighas2.4pt/Amaybeapplied,dependingonsoiltexture.
Annualgrassesandbroadleafweedsincludingcocklebur,devil’sclaw,lambsquarters,morningglory,piemelon,pigweed
Linex4L1.0–3.0pt(linuron)
7Postemergencedirectedtocottonatleast12in.tall
Ratesvarybasedupontheheightofcotton,refertolabelformoreinstructions.Add1.0ptsurfactantforeach25galofspraysolution.
Selectedgrasses,broadleafweeds,andsedges.Refertolabel
MSMA62.66pt(MSMA)
17
Postemergencedirectedtocottonbetween3in.tallandfirstbloom.
Applyat40galwater/A.Ifregrowthoccurs,asecondapplicationmaybemade1to3weeksafterthefirst.Donotapplyafterfirstbloom.Donotfeedtreatedfoliagetolivestock.
Preemergencecontrolofmanyannualgrassesandsmall-seededbroadleafweeds,postemergencecontrolofbroadleafandsomegrassweeds
Prefix2.0–2.33pt(S-metolachlor+fomesafen)
14,15Postemergencedirectedtocottonatleast6in.tall
Applytobroadleafweedswith2to4trueleavesinaminimumof10galwater/A.Addanonionicsurfactantat0.25to0.50%v/voracropoilconcentrateat1.0%v/v.Donotaddliquidnitrogenfertilizer.InTexas,onlyuseinareaseastofU.S.Highway77andnorthofStateRoad239,includingallofCalhounCounty.
24
Table6continued.Post-directedorhoodedherbicideoptions
Annualgrassesandsmall-seededbroadleafweeds
ProwlH2O1.0–4.0pt(pendimethalin)
3Postemergencedirectedtocottonafterlayby
Rateof1to3pt/Aonconventionalorminimaltillage,2to4pt/Aonno-till.Checklabelformaximumlabelledratesbaseduponsoiltexture.
Annualandperennialgrassandbroadleafweeds
Glyphosateproductsratesvaried,refertolabel(glyphosate)
9
Postemergenceusinghoodedsprayerstonon-glyphosatetolerantcotton
Applyin20to30galwater/A.Extremecaremustbetakentopreventcontactofglyphosatewithfoliageofnon-glyphosatetolerantcotton.
Annualbroadleafweeds,suppressionofsomeannualgrasses
Reflex1.0–1.5pt(fomesafen)
14
Postemergencedirectedtocottonfrom6to12inchestall,orasalaybytocottonwithatleast4inchesofbarkonstem
Applyonlytocoarsetexturedsoils,ascropinjurymayoccuronmediumandfinesoils.OnlylabelledforuseinTexasforareaseastofU.S.Highway77andnorthofStateRoad239,includingallofCalhounCounty.FIFRASection24(c)label:MaybeusedwestofHwy277fromWichitaFallstoAnson,andnorthofHwy180totheNMandOKstatelines.IncludesFisher,Scurry,Borden,andDawsoncounties.Apply1.0pt/Ainatleast10gal/Aspraysolution.ApplicationsmaybemadeuptoJuly10.Include0.25%v/vnonionicsurfactantor1.0%v/vcropoilconcentrate.Rotationalrestrictionsare24monthsforwheat,andmorethan36monthsforsorghum.
SedgesandbroadleafweedsSandea0.66–1.33oz(halosulfuron)
2
Postemergenceusinghoodedsprayeranytimeaftercottonemergenceuntilrowclosurebycotton
Providesbothpreemergenceandpostemergenceweedcontrolofsusceptiblespecies.Forcontrolofemergedweeds,treatwhenactivelygrowingand1–3in.inheight.Addanonionicsurfactantat0.25to0.50%v/v.Donotapplymorethan1.33ozperseason.
25
Table6continued.Post-directedorhoodedherbicideoptions
Selectedbroadleafweeds,grasses,sedges
Suprend1.0–1.5lb(prometryn+trifloxysulfuron)
2,5Postemergencedirectedtocottonatleast6in.tall
ForuseinpickerandPimacottonvarietiesonly.DonotapplyintheRioGrandeValley.Donotapplywithin60daysofcottonharvest.Donotexceed2.7lb/ASuprendperseason.
Annualgrassesandsmall-seededbroadleafweeds
Treflan4EC1.0–2.0pt(trifluralin)
3
Postemergencedirectedtocottonfrom4leafstagetolayby
Soilincorporateusingonepassofasweep-typecultivatororaproperlyadjustedrollingcultivator.Donotharvestwithin90daysofapplication.
ManyannualbroadleafwedsValorSX1.0–2.0oz(flumioxazin)
14
Postemergencedirectedthroughhoodedorshieldedsprayers,ordirectedsprayatlayby
Forhoodedorshieldedsprayerapplications,applyonlytocottonthatisatleast6in.tall.Laybyapplicationsmaybemadeaftercottonreaches16in.height.Onlyuseanonionicsurfactant.Cropoilconcentratesormethylatedseedoilsmayresultinseverecropinjury.
Annualgrasses,sedges,andannualbroadleafweeds
Zidua0.75–2.1oz(pyroxasulfone)
15
Postemergencedirectedtocottonbetween5leafstageandfirstbloom
SomecottoninjurymaybeobservedwhenZiduaisappliedunderstressfulconditions.Willonlycontrolweedsemergingafterapplication.Donotuseoncoarsetexturedsoils.
26
Table7.Wickorwiperappliedherbicideoptions
WeedsControlledProduct,Rate/A,ActiveIngredient
Group#
TimetoApply Notes
Manyannualandperennialgrassandbroadleafweeds
RoundupWeatherMAX33-75%solution(glyphosate)
9Whenweedsareatleast6in.abovethecottoncrop.
Donotwipeanycloserthan2in.abovethecottoncrop.Asweeddensityincreases,reducespeed.Wipingasecondtimeintheoppositedirectionmayimprovecontrol.Donotusewiperwhenweedsarewet.Oversaturationofwipermaycausedrippingwhichwillinjurethecrop.Concentrationusedishighlydependentonthewickorwiperdevicechosen,consultmanufacturer.
27
PHOTOGRAPHSOFCOMMONWEEDS
BalloonvineCardiospermumhalicacabum
Annualvinesprawlingandtrailing.Leavesalternate,usuallytwicealternatelycompound.Leafletstoothedandlobed.Flowersabout4mmlongwith4petals.Fruitsinflated(balloon-like).
BarnyardgrassEchinochloacrus-galliAnnualsummergrass.Leafsheathandbladehairlesswithnoliguleorauricles.Stemsflattened.Spikelets3to4mmlong.
Bindweed,fieldConvolvulusarvensisPerennialtrailingvinewithdeeproot.Gray-greenpubescence.Simple,alternateleaves,usuallylanceolateinshape.Flowerstypicallywhitewithfivefusedpetals.
28
BrowntoppanicumUrochloafasciculatumAnnualsummergrass.Spreadingorerectgrowthformspossible.Ligulesofhairsapproximately1mmlong.Panicleswithappressedbranches.
CommoncockleburXanthiumstrumariumSummerannual.Smooth,waxycotyledonslanceolateinshape.Alternateleavestriangularorovateinshapewitharough,sandpapertexture.
CommonsunflowerHelianthusannuusSummerannual.Ovatecotyledons.Alternatesimpleleaveswithroughtextureandhairs.Leaveswithserratemarginstaperedtoapoint.
29
CutleafgroundcherryPhysalisangulateSummerannual.Mostlywithouthairs.Leavesovatetoovate-lanceolatewithtoothedmargins.Paleyellowflowers5-sided.Stemangledincross-sectionandhollow.
Devil’sclawProboscidealouisianicaLow,bushysummerannual.Odiferousandcoveredwithglandularhairs.Leavesalternateoroppositeandmostlyovateinshape.Yellowfive-lobedflowers.Fruitafleshycurvedpod,splittingintotwo“claws”afterdesiccation.
HophornbeamcopperleafAcalyphaostryifoliaErectannual,freelybranched.Long-petioledleaves,nearlyglabrous.Leavesalternatewithfinelytoothedmargins.
30
HorseweedConyzacanadensisWinterorsummerannual.Smooth,spatulatecotyledons.Earlyleaveswithentiremargins,laterleavescrowdedaroundthestemwithentireortoothedmarginsandoftenhairy.
IvyleafmorninggloryIpomoeahederaceaAnnualtwiningvinewithpubescentstems.Leavestypically3-lobed,occasionallywithoutlobes.Funnel-shapedflowers(corolla),typicallylightbluewithwhiteoryellowcenters.
JohnsongrassSorghumhalepensePerennialgrass.Leafsheathandbladehairlesswithnoauricles.Largemembranousliguleswithjaggedmargins.Oval,shinyseed.Mayalsoreproduceviarhizomes.
31
JunglericeEchinochloacolonaSummerannualgrass.VerysimilarinappearancetoE.crus-galli(barnyardgrass).Leavesmayexhibitseveralpurplebandsacrossthem.
KochiaKochiascopariaSummerannual.Narrow,oblongcotyledonswithmanysoft,finehairs.Leavesalternateandsimplewithmanyhairs,andwithoutpetioles.
LanceleafSageSalviareflexaSlightlyhairyannualreaching1to1.5fttall.Oppositeleaveslanceolatewithtoothedorentiremarginsandshortpetioles.Stemssquareincross-section.Flowerswithbluetowhitepetals.
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Nutsedge,yellowCyperusesculentusPerennial,colonialsedge.Stemstriangularincross-section.Leavesarrangedinranksofthreeandgraduallyformapointedtip.Rhizomessometimeswithtubersformingattheends.
Nutsedge,purpleCyperusrotundusPerennial,colonialsedge.Stemstriangularincross-section.LeavesarrangedinranksofthreeandformamoreroundedtipthanC.esculentus(yellownutsedge).Rhizomesmayformchainsoftubersalongtheirlength.
PalmeramaranthAmaranthuspalmeriDioecioussummerannual.Cotyledonslinearandwithouthairs.Leavesmostlyglabrous.Petiolesoftenlongerthanleafblades.Faintwhitechevronmarkingsmaybepresentonleaves.
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PartheniumragweedPartheniumhysterophorusAnnualbroadleafresemblingtheappearanceofwesternragweed.Seedlingformsabasalrosette,whichlatergrowsto0.5–1.5mtall.Stemslongitudinallygroovedwithstiffhairs.Laterleavesarealternateanddeeplydivided.Flowersarewhiteandforminnumerousclusters.
PuncturevineTribulusterrestrisProstrateannualbroadleaf.Leavespinnatelycompoundandopposite.Leafletspubescentatthemidveinandmarginsabove,denselypubescentbelow.Flowerswith5yellowpetals.Fruitisaspinycapsule.
Purslane,commonPortulacaoleraceaSprawlingsummerannual.Cotyledonslinearandwithouthairs.Oppositeleaveswhicharesmoothandspatulate.Leavesandstemsaresucculent.
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ProstrateSpurgeChamaesyceprostrataSprawling,prostrateannual.Leafbladesbroadlyelliptic,withshortornopetioles,andarrangedopposite.Leavesfoldingtogetheratnightorunderpoorconditions.Brokentissueexudesamilkysap.
RussianThistle,tumbleweedSalsolaibericaBushyannual.Stemsmayhavered-purplestreaks.Leavesarefiliform.Flowerslackpetalsandaresubtendedbyapairofspinybracts.Theplantdriesandbreaksoffatthebaseinthefall,formingaround“tumbleweed.”
SharppodmorninggloryIpomoeatrichocarpaPerennialvinewithtwining,climbingstems.Leavesalternatewithpubescence,typically3-lobedorheart-shaped(chordate).Flowersusuallyredtored-purplewithadarkredcenter.
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SilverleafNightshadeSolanumeleagnifoliumPerennialbroadleaf.Stemsandleaveshaveasilverappearanceduetomanystellatehairs.Stemsmaybedenselyprickly.Leavesarelinear.Flowersblue-purple,occasionallywhite.
TexasBlueweedHelianthusciliarisPerennialwithslenderrhizomes.Stemsandleaveswithablue-greencast.Leavesaremostlyopposite,lanceolate,withshortpetioles.Rayflowersyellow,diskflowersreddish-bronze.
TexaspanicumUrochloatexanaAnnualgrass,spreadingtoerectingrowthhabit.Ligulesofhairsapproximately1mmlong.Broad,hairyleaves.Panicleswithappressedbranches.SimilarinappearancetoU.fasciculate(browntoppanicum),exceptforslightlyshorterpubescenceonleaves.
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Waterhemp,commonAmaranthusrudisSummerannual.Linearcotyledons.Leavesnarrowlyovatetolanceolate,alternate,andwaxyinappearance.Plantwithouthairs.Petiolesmaybeshorterthanleaves.
WoolyleafBursageAmbrosiagrayiPerennialreaching6to24inchestall.Pinnatelylobedleaves,oppositeinarrangement,withagraycastduetodensepubescence.Fruitbecomesaburaftermaturity.
VelvetleafAbutilontheophrastiSummerannual.Eachcotyledondiffersinshape;oneisovate,whiletheotherischordate(heart-shaped).Bothcotyledonswithentiremarginsandcoveredinshorthairs.Stemsaredenselyhairy.Leaveschordate,andalternatewithsoft,velvetyhairysurfaces.
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DepartmentofSoilandCropSciencesTexasA&MAgriLifeExtensionService
TexasA&MUniversity
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