turfgrass weed management ii. broadleaf weed control

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Turfgrass Weed Management II. Broadleaf Weed Control. Tim R. Murphy Crop and Soil Sciences The University of Georgia. Broadleaf Control. Most broadleaf control is done with postemergence herbicides. The essential broadleaf herbicides are: Postemergence - growth regulators and sulfonylureas - PowerPoint PPT Presentation


  • Turfgrass Weed ManagementII. Broadleaf Weed ControlTim R. MurphyCrop and Soil SciencesThe University of Georgia

  • Broadleaf ControlMost broadleaf control is done with postemergence herbicides.The essential broadleaf herbicides are:Postemergence - growth regulators and sulfonylureasPre and post atrazine, simazine, metribuzin.Pre only - Gallery

  • Growth Regulator Herbicides


    Picolinic Acid

    Benzoic Acid





    Turflon D




  • Broadleaf HerbicidesThere are many growth regulator combinations on the market.Mixtures of broadleaf-active herbicides tend to control more weed species than each individual component herbicide.

  • Phenoxy + Dicamba Herbicides

  • Phenoxy + Dicamba Herbicides

  • Phenoxy, Dicamba, Picolinic Herbicides

  • Post Herbicide Use GuidelinesTry to avoid spraying warm-season grasses during transition.Shade grasses are less herbicide tolerant than grasses growing in full sun.Spray when wind speeds are less than 5 mph.

  • Post Herbicide Use GuidelinesAvoid stress conditions (> 90 F.)Avoid spring transition on warm-seasonsRepeat applicationsDo not mow 24 to 48 hours before or after applicationRainfall and irrigation effects

  • Post Herbicide Use GuidelinesDo not water for 12-24 hours.

    Need a rain free period of at least 6 hours.

    Avoid extreme temperatures. Apply when temperatures are between 40 and 80F.

  • Examples of Rain-Free PeriodsMSMA - 24 hoursTrimec Classic - 24 hoursBasagran T/O - 8 hoursFinale - 4 hoursVantage - 1 hour

  • Post Herbicide Use GuidelinesAnnual weed control is excellent in the seedling stage and poor as the weed maturesPerennial weeds are more susceptible in the Spring or Fall because root reserves are usually depleted and the weed has less recovery potentialApply to actively growing weeds - the cuticle is more easily penetratedSprays give better control than granules.

  • Post Herbicide Use GuidelinesRepeat applications are most effective for tough perennials.Apply during good growing conditions when adequate soil moisture is present.Add a surfactant if called for on label.

  • Low growing winter annuallawn burweedfruitPre or postemergence atrazine or simazine in mid-fall. Prompt and Sencor are also effective on tolerant turfgrasses. Repeat applications of 2 or 3-way 2,4-D type herbicides. The key is applying in the fall when the weeds are small

  • common chickweedwinter annual

  • winter annualsticky chickweed

  • henbitwinter annualHenbit

  • winter annualPurple deadnettle

  • henbitpurple deadnettlewinter annuals

  • winter annualhairy bittercress

  • fruitwinter annualshepherds purse

  • annual or biennialpurple cudweed

  • winter annualparsley-piert

  • winter annualseedlingcorn speedwell

  • Virginia buttonweedDifficult to control. Try digging if there are only a few plants.Repeat applications of 3-ways or 2,4-D about 4 weeks apart are needed for adequate suppression.2,4-D seems to have the most activity.

  • Dandelion - Perennial2,4-DTrimecConfrontDrive

  • wild violet - perennialTriclopyr-containing formulations (Turflon, Confront)Some think dichlorprop is better on violet.Confront requires careful use in warm-season. Safe in fescue.

  • white clover - perennialConfront, Lontrel and Manor are very effective. Warm-season grasses should be dormant or fully greened-up..Lontrel and Manor have greater turf safety than Confront.Trimec or other 3-ways are effective. May take two applications.

  • winter annualSpotted burclover

  • Annual lespedezaSummer annual

  • Chamberbitter, niruriSummer annualBrought to Georgia in ornamental container plants.Atrazine or simazine applied twice, 30 days apart. Prompt also works well. 2 or 3-way broadleaf mixtures applied 7 days apart are also effective in tolerant turfgrasses.

  • prostrate spurge - summer annualPostemergence: Manor, Sencor, TrimecPreemergence: Simazine, atrazine, Gallery

  • summer annualfireweedThe 2 and 3-way growth regulator herbicides and Manor. Preemergence products are not very effective or provide only short term control.American burnweed (fireweed)

  • Pennywort or dollarweedperennialAtrazine or simazine applied twice, 30 days apart. Prompt also works well. Image, Drive and Manor.2- or 3-way broadleaf mixtures applied 7 days apart are also effective in tolerant turfgrasses.

  • Dichondra, rhizomatous perennialControlled by repeat applications of atrazine, 30 days apart.2 and 3-way growth regulator herbicides. Confront is a little better than Trimec related compounds.

  • perennialground ivy

  • buckhorn plantainperennial

  • perennialblackseed plantain100% ControlConfront 2 pts/acreTrimec 4 pts/acre

  • perennialwoodsorrel (Oxalis spp.)

  • Non-Target PlantsCheck for restrictions on the use of herbicides around trees and shrubs.Be very careful around vegetables and ornamentals with growth regulator herbicides.Avoid applying dicamba and atrazine under shallow rooted ornamentals such as azalea and rhododendron.

  • Nonselective ControlRoundup Pro - Do not tank mix with Reward or Finale if you are trying to control perennials.Rapid burndown prevents translocation of Roundup through the plant.

  • Nonselective Broadleaf ControlRoundup Pro - slow acting (7-14 days) but provides the best control of perennials.Reward - fastest burndown, poor perennial control, poor grass control.Finale - Almost as fast as Reward, will leave a straight edge, very good on white clover and other legumes. Not good on perennials.

  • Lack of Post Herbicide PerformanceEnvironmental stressesWeed growth stageRain/irrigation wash-offNo adjuvantPoor spray coverage

  • Lack of Post Herbicide PerformanceWrong rateWrong herbicideNo follow-up applicationMowing effects


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