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 Pre and post atrazine simazine metribuzin Pre only Gallery Growth Regulator Herbicides Phenoxy Picolinic Acid Benzoic Acid 2 4 D Lontrel Banvel dichlorprop Turflon D Vanquish mecoprop MCPA Broadleaf Herbicides There 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 Herbicide Weedar 64 2 4 D MCPP MCPA 2 4 DP dicamba X MCPP 4 X 2 Plus 2 X Four Power X Turf D DP X X X X Trimec Classic X X X Trimec Southern X X X Phenoxy Dicamba Herbicides Herbicide 2 4 D MCPP MCPA Triamine X Triamine II Tri Power Dissolve X Triplet X Triplet Sens X X X X X X X X X 2 4DP dicamb a X X X X X X Phenoxy Dicamba Picolinic Herbicides Herbicide 2 4D MCPA clopyral id Lontrel triclop yr dicam ba X Turflon Ester X Confront X X Chaser ester X X Chaser II Am X X Cool Power ester X X X HorsePower X X X Post Herbicide Use Guidelines Try 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 Guidelines Avoid stress conditions 90 F Avoid spring transition on warmseasons Repeat applications Do not mow 24 to 48 hours before or after application Rainfall and irrigation effects Post Herbicide Use Guidelines Do not water for 12 24 hours Need Avoid a rain free period of at least 6 hours extreme temperatures Apply when temperatures are between 40 and 80 F Examples of Rain Free Periods MSMA 24 hours Trimec Classic 24 hours Basagran T O 8 hours Finale 4 hours Vantage 1 hour Post Herbicide Use Guidelines Annual weed control is excellent in the seedling stage and poor as the weed matures Perennial weeds are more susceptible in the Spring or Fall because root reserves are usually depleted and the weed has less recovery potential Apply to actively growing weeds the cuticle is more easily penetrated Sprays give better control than granules Post Herbicide Use Guidelines Repeat 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 growin g winter annual fruit lawn burweed Pre 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 winter annual common chickweed sticky chickweed winter annual Henbit henbit winter annual winter annua l Purple deadnettle winter annuals henbit purple deadnettle winter annual hairy bittercress winter annual shepherd s purse fruit annual or biennial purple cudweed winter annual parsley piert seedling winter annual corn speedwell Virginia buttonwee d Difficult 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 2 4 D Trimec Confront Drive Dandelion Perennial wild violet perennial Triclopyr containing formulations Turflon Confront Some think dichlorprop is better on violet Confront requires careful use in warm season Safe in fescue white clover perennial Confront 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 Spotted burclover winter annual Annual lespedeza Summer annual Chamberbitter niruri Brought to Georgia in Summer annual 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 annual Postemergence Manor Sencor Trimec Preemergence Simazine atrazine Gallery fireweed American burnweed fireweed The 2 and 3 way growth regulator herbicides and Manor Preemergence products are not very effective or provide only short term control summer annual perennia l Pennywort or dollarweed Atrazine 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 Controlled by repeat applications of atrazine 30 days apart Dichondra rhizomatous perennial 2 and 3 way growth regulator herbicides Confront is a little better than Trimec related compounds perennial ground ivy perennial buckhorn plantain perennial 100 Control Confront 2 pts acre Trimec 4 pts acre blackseed plantain perennial woodsorrel Oxalis spp Non Target Plants Check 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 Control Roundup 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 Control Roundup 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 Performance Environmental stresses Weed growth stage Rain irrigation wash off No adjuvant Poor spray coverage Lack of Post Herbicide Performance Wrong rate Wrong herbicide No follow up application Mowing effects