Herbicidesherbicides Briefbrief Herbicideherbicide Schoolschool Whatwhat Isis Aa Herbicide?Herbicide?
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ConsumerConsumer ProductsProducts forfor HomeHome LawnLawn andand LandscapeLandscape WeedWeed ControlControl RonRon StrahanStrahan WeedWeed ScienceScience BasicsBasics TypesTypes ofof WeedsWeeds •• BroadleavesBroadleaves –– – Netted veination Virginia – 2 cotyledons buttonweed – Taproot – Showy flowers •• GrassesGrasses –– – Parallel – 1 cotyledon Crabgrass – Fibrous roots •• SedgesSedges –– “nutgrass” purple nutsedge – Triangular stems – Leaves in 3’s OptionsOptions forfor WeedWeed ControlControl •• EncouragingEncouraging turf/cropturf/crop growthgrowth •• MowingMowing •• HandHand pulling/hoeingpulling/hoeing 99HerbicidesHerbicides BriefBrief HerbicideHerbicide SchoolSchool WhatWhat isis aa herbicide?herbicide? AA chemicalchemical oror materialmaterial whichwhich injuresinjures oror killskills aa plant.plant. HerbicideHerbicide DefinitionsDefinitions •• ActiveActive ingredientingredient –– moleculemolecule thatthat providesprovides herbicidalherbicidal actionaction – Glyphosate – Roundup, Eraser etc – Trifluralin – Preen, Treflan •• ModeMode ofof actionaction –– physiologicalphysiological processprocess thatthat leadsleads toto negativenegative plantplant effectseffects – Photosynthesis inhibitor - Atrazine – Mitosis disruptor – Preen – Amino acid production disrupted - Roundup TypesTypes ofof HerbicidesHerbicides 1/31/3 •• NonselectiveNonselective –– killskills everythingeverything –– e.g.e.g. Roundup,Roundup, FinaleFinale •• SelectiveSelective –– controlscontrols certaincertain plantsplants andand releasesreleases otherother speciesspecies –– e.g.e.g. WeedWeed--BB--Gone,Gone, Vantage,Vantage, AtrazineAtrazine TypesTypes ofof HerbicidesHerbicides 2/32/3 •• ContactContact –– burnsburns backback whatwhat onlyonly whatwhat itit hitshits –– e.g.e.g. Diquat,Diquat, MSMA,MSMA, FinaleFinale •• TranslocatingTranslocating (systemic)(systemic) –– movemove throughoutthroughout plantplant –– e.g.e.g. WeedWeed--BB--Gone,Gone, Vantage,Vantage, RoundupRoundup TypesTypes ofof HerbicidesHerbicides 3/33/3 •• PreemergencePreemergence –– WeedWeed preventor/residualpreventor/residual herbicidesherbicides –– controlscontrols weedsweeds beforebefore youyou seesee themthem •• PostemergencePostemergence –– killskills weedsweeds thatthat areare activelyactively growinggrowing PreemergencePreemergence HerbicideHerbicide InformationInformation EffectiveEffective PreemergencePreemergence ApplicationApplication •• ApplyApply beforebefore weedsweeds germinategerminate •• AdequateAdequate rainfallrainfall oror irrigationirrigation isis neededneeded •• DoDo notnot expectexpect allall seasonseason longlong controlcontrol -- mightmight reapplyreapply HowHow dodo preemergencepreemergence herbicidesherbicides work?work? 99TheyThey provideprovide aa lethallethal barrierbarrier atat oror justjust belowbelow soilsoil surface.surface. HowHow DoDo PreemergencePreemergence HerbicidesHerbicides Work?Work? YouYou cancan breakbreak downdown thethe barrierbarrier easilyeasily inin aa flowerbed!flowerbed! 99Walking,Walking, transplanting,transplanting, dogs,dogs, catscats cancan breakbreak herbicideherbicide barrierbarrier prematurelyprematurely byby disturbingdisturbing thethe soil.soil. WhenWhen ShouldShould II ApplyApply PreemergencePreemergence HerbicideHerbicide inin Turf?Turf? BeforeBefore theythey emergeemerge !! CrabgrassCrabgrass •• SummerSummer annualannual •• ProducesProduces lotslots ofof seedseed •• GerminatesGerminates -- soilssoils reachreach 5353 -- 58F58F •• LightLight isis requiredrequired forfor germinationgermination GoosegrassGoosegrass •• SummerSummer annualannual •• ProducesProduces lotslots ofof seedseed •• GerminatesGerminates -- soilssoils reachreach 6060--65F65F •• LightLight isis requiredrequired forfor germinationgermination SomeSome commoncommon consumerconsumer PreemergencePreemergence herbicidesherbicides CrabgrassCrabgrass PreventorPreventor (Team)(Team) •• GreenlightGreenlight ProductProduct •• BenefinBenefin ++ TrifluralinTrifluralin •• AnnualAnnual grassesgrasses andand smallsmall seededseeded broadleavesbroadleaves •• UseUse onon establishedestablished turfturf onlyonly •• AvailableAvailable atat mostmost nurseriesnurseries AmazeAmaze HerbicideHerbicide •• BenefinBenefin ++ oryzalinoryzalin •• Rate:Rate: 44 lbslbs // 888888 sq.sq. ft.ft. •• Crabgrass,Crabgrass, goosegrass,goosegrass, annualannual bluegrass,bluegrass, andand smallsmall seededseeded broadleavesbroadleaves •• GreenlightGreenlight productproduct •• MostMost annualannual andand perennialperennial ornamentalsornamentals toleranttolerant Preen/TreflanPreen/Treflan HerbicideHerbicide • Trifluralin • Annual grasses and small seeded broadleaves • Safe in most flower beds over the top of annual and perennial plants • Available at most nurseries, Lowes, Home Depot, Wal Mart • Little more volatile than most herbicides ConsumerConsumer preemergencepreemergence herbicidesherbicides withwith dithiopyrdithiopyr asas activeactive ingredientingredient CrabgrassCrabgrass PreventorPreventor 22 •• DithiopyrDithiopyr •• AnnualAnnual grassesgrasses andand smallsmall seededseeded broadleavesbroadleaves •• WillWill killkill smallsmall emergedemerged crabgrasscrabgrass •• MostMost gardengarden centerscenters StaSta--GreenGreen CrabCrab--EXEX •• DithiopyrDithiopyr •• AnnualAnnual grassesgrasses andand smallsmall seededseeded broadleavesbroadleaves •• WillWill killkill smallsmall emergedemerged crabgrasscrabgrass •• FindFind itit atat LowesLowes HiHi--YieldYield DimensionDimension HerbicideHerbicide •• DithiopyrDithiopyr •• AnnualAnnual grassesgrasses andand smallsmall seededseeded broadleavesbroadleaves •• WillWill killkill smallsmall emergedemerged crabgrasscrabgrass •• CanCan alsoalso bebe usedused inin flowerbedsflowerbeds Herbicides can cause root inhibition dithiopyr on Crabgrass Halts (ai) on bermudagrass zoysiagrass Preventor (ai) on St. Augustinegrass Swollen, stubby, club shaped roots prevent “rooting down”. PreemergencePreemergence broadleafbroadleaf controlcontrol (that(that’’ss safesafe aroundaround trees)trees) PortraitPortrait herbicideherbicide •• KillsKills broadleafbroadleaf weedsweeds beforebefore theythey emergeemerge •• IsoxabenIsoxaben –– samesame ingredientingredient inin GalleryGallery •• ExcellentExcellent forfor winterwinter broadleafbroadleaf controlcontrol •• NoNo grassgrass activityactivity •• ApplyApply inin OctoberOctober •• ApplyApply justjust beforebefore oror afterafter CrabgrassCrabgrass PreventorPreventor forfor broadbroad spectrumspectrum weedweed controlcontrol •• GoodGood preemergencepreemergence lawnlawn burweedburweed controlcontrol ••NOTE:NOTE: BeBe CarefulCareful withwith AtrazineAtrazine !! 9Near trees and shrubs 9Especially newly planted 9Terrific when used properly 9Weed and Feed problems in flower beds usually are from ATRAZINE products. AtrazineAtrazine HerbicideHerbicide • Best for practically all winter weeds – apply in Nov. and reapply in Feb. if necessary • Be careful around trees, ornamentals and bermudagrass • Liquid formulation – prefer liquid over weed and feed • Better as a preemergence or early postemergence • Our favorite general winter weed control WeedWeed andand FeedsFeeds •• UsuallyUsually containscontains atrazineatrazine •• BeBe CarefulCareful aroundaround flowerflower beds,beds, shrubsshrubs andand treestrees •• LateLate--MarchMarch throughthrough AprilApril applicationsapplications •• WeWe areare notnot ‘‘bigbig fansfans’’ ofof thesethese productsproducts •• WeWe preferprefer addressingaddressing weedweed problemproblem separatelyseparately NonNon--selectiveselective HerbicidesHerbicides GlyphosateGlyphosate HerbicideHerbicide •• E.g.E.g. Roundup,Roundup, HiHi--YieldYield KillzallKillzall,, EraserEraser etc.etc. •• Lb.Lb. forfor lb.lb. therethere isis nono differencedifference inin controlcontrol •• WillWill killkill oror injureinjure mostmost plantsplants •• AA systemicsystemic herbicideherbicide thatthat isis goodgood onon perennialperennial weeds.weeds. •• TotallyTotally deactivateddeactivated whenwhen itit hitshits soilsoil – No residual activity. •• VisualVisual symptomssymptoms inin 22--44 daysdays inin growinggrowing pointspoints SeveralSeveral RoundupRoundup FormulationsFormulations • 18%, 41%, 50% glyphosate • ‘Ready to use’ products also; usually < 2% strength • Some have diquat added – strictly for consumer – gives superficial burn • Newest - Roundup Extended – also contains diquat and imazapic – Around trees – Patios – bricks and driveways, gravel areas – Do not spray in flower beds • Roundup Brush Killer – has triclopyr for woody broadleaf control AzaleasAzaleas && tomatoestomatoes areare sensitivesensitive toto Roundup/glyphosateRoundup/glyphosate driftdrift Glyphosate on tomato Rubber/CottonRubber/Cotton GloveGlove ApplicationApplication MethodMethod RubberRubber Glove/CottonGlove/Cotton GloveGlove • 4 oz glyphosate in 32 oz water • Rubber glove inside cotton glove • Dip and squeeze off excess • Use ungloved hand to remove desirable foliage • Gently wipe only weed leaves FinaleFinale HerbicideHerbicide •• NonNon--selectiveselective •• GlufosinateGlufosinate –– activeactive ingredientingredient •• NoNo soilsoil residualresidual •• AlternativeAlternative toto RoundupRoundup (glyphosate)(glyphosate) •• NotNot quitequite asas goodgood onon perennialperennial grassesgrasses PostemergencePostemergence HerbicidesHerbicides forfor TurfgrassTurfgrass PostemergencePostemergence HerbicideHerbicide FactsFacts •• EasierEasier toto controlcontrol smallsmall activelyactively growinggrowing weedsweeds •• SomeSome temporarytemporary