Bertie County Tobacco Tips

Jarette Hurry

June 2017

Topping tobacco in the button stage (soon after the flower begins to appear) rather than late increases yield and body if suckers are controlled. When tobacco plants are not topped for three weeks after reaching the button stage, yields are reduced by 20 to 25 pounds per acre per day, or close to 1% per acre per day when normal yields range from 2,000 t- 2,500 pounds per ace.

Thefirstcontactapplicationshouldbemadeassoonas50%to60%oftheplantshaveavisiblebutton.TimingofChemicalapplicationisimportantbecauseneithercontactsnorflumetralinwilladequatelycontrol suckers longer thanone inch. Coverageof leafaxilsand stalk rundownareessentialforcontactapplications.Contactsshouldbeappliedwiththreenozzlesperrow,atlowpressurewith50gallonsperacredeliveryvolume.ThesuggestedrationforthefirstapplicationofC8-C10contactalcoholproductsistwogallonsin48gallonsofwater;thismakesa4%solution.A5%solutionissuggestedforthesecondorthirdapplication;thisis2½gallonsin47.5gallonsofwater.

Contactsaremoreeffectiveifappliedthreetofivedaysapartwhenhumidityislowandleafaxilsarefullyexposed.Thisisgenerallybetween10amand6pmonsunnydays,exceptwhenplantsarewiltedandtemperaturesexceed90°F.Contactsshouldnotbeappliedtoplantsthatarewetwithrainorheavydeworthatareseverelydroughtstressed.

Contacts(FattyAlcohols)

Flumetralinshouldbeappliedlikeacontactsolutionbutnotuntiltheplantsareintheelongatedbuttontoearlyflowerstage.Theobjectiveistoapplyflumetralinsothatittouchesthesmallsuckerslikecontactsolutions do because, unlike MH, flumetralin does not move to sucker buds through the leaves.Flumetralinmustfirstwetthesuckerslikea fattyalcoholcontactbefore itcanstopcelldivision likeasystemic.Flumetralinshouldbeappliedlikeacontactsolution.Eventhoughtheflumetralinlabelallowsforapplicationofuptoonegallonperacre,thegeneralrecommendationhasbeenforapplicationratesoftwoquartsperacre.Increasingflumetralinratesfromquartsperacretothreequartsoronegalloninasinglemechanicalapplicationhasnotconsistentlyimprovedsuckercontrol,primarilybecausecontrolisso dependent on coverage of all leaf axils, which is not improved by increasing flumetralin rates.However,applicationoftwoquartsofflumetralinfollowedbyonequartofflumetralinsevendayslaterimproves sucker control compared to three quarts of flumetralinapplied ina single application. Thiswouldindicatethatincreasingratesofflumetralinabovetwoquartsperacreisonlyadvantageousiftheflumetralinisappliedinasplitapplication.Itislikelythatsplitapplicationsreducethenumbermissedleafaxils.

UseofFlumetralin

Unlikefattyalcoholcontactsandflumetralin,MHisabsorbedbyleavesandmoveswithintheplanttosmallsucker buds. Good absorption and systemic movement depends on having good crop growing conditions.Therefore,MHshouldneverbeappliedondroughtstressedcropsoronthosewiltedbytoomuchrain,hightemperatures,orboth.Ifsoilmoistureisadequatebutafternoontemperatureswillbehighenoughtocausepartialwilting,MHshouldbeappliedonlyduringthemorning,startingwhentheleavesarejustslightlywetwithdew. AfternoonSprayinggenerallyisnotsuggestedexceptoncool,cloudydayswhensoilmoistureisgood.

MHisabsorbedmoreeffectivelybyyounger,upperleavesthanbyolder,lowerleaves.Therefore,MHshouldbeappliedtotheupperthirdoftheplantusingthethree-nozzles-per-rowarrangement.

MostMHlabelsstipulatethatitmustnotbeappliedbeforetheupperleavesareeightincheslongtoreducepossible stunting, a discoloration called “bronzing”, or both. These abnormalities are sometimes observedwhen MH is applied on leaves longer than eight inches. Growth distortion of upper leaves treated withflumetralinalsooccurs,butlessfrequentlythanthatassociatedwithMH.Researchsuggeststhatthelikelihoodof discoloration and stunting fromMH applications is greatly reducedwhen applications are delayed untilupperleavesare16incheslong.

KnowhowmuchMHisintheproductyouuse.Forexample,oneproductcontains1.50poundsactiveingredientperacrewhichwouldrequire1gallon/acre.Anotherproductcontains2.25poundsactiveingredientperacrewhichonlyrequires.66gallonsperacre.Yourtargetrateshouldbe1.5pounds’activeingredientperacre.

MHresiduescanalsobereducedwhentheintervalbetweenapplicationandharvestismaximized.TheMHlabelstatesthatyoushouldwaitatleastsevendaysbetweenMHapplicationandharvest,withtheanticipationthatrainfallduringthisperiodwillwashoffsomeresidues.IftobaccoisreadyforMHapplicationandharvest,makeeveryattempttoharvestfirst,thenapplyMH.DelayharvestafterMHapplicationaslongaspossible.Itwillmostlikelybeatleastsevendaysbeforethecropwillbereadyforanotherharvest.ThiswillensureMHfreefirstprimings.

ForMoreinformationonsuckercontrolreferencechapter7inthe2016FlueCuredTobaccoProductionguide.

MH

JaretteHurryBertieCountyCenterNorthCarolinaCooperativeExtension104DundeeSt.,POBox280Windsor,NC27983Email–jarette_hurry@ncsu.eduPhone(252)794-5317Fax(252)794-5375

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