turfgrass weed management ii. broadleaf weed control

Turfgrass Weed ManagementTurfgrass Weed ManagementII. Broadleaf Weed ControlII. Broadleaf Weed Control

Tim R. MurphyCrop and Soil Sciences

The University of Georgia

Broadleaf ControlBroadleaf 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 HerbicidesGrowth Regulator Herbicides

Phenoxy Picolinic Acid Benzoic Acid

2,4-D Lontrel Banvel

dichlorprop Turflon D Vanquish

mecoprop

MCPA

Broadleaf HerbicidesBroadleaf 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 HerbicidesPhenoxy + Dicamba Herbicides

Herbicide 2,4-D MCPP MCPA 2,4-DP dicamba

Weedar 64 X

MCPP-4 X

2 Plus 2 X X

Four Power + X X

Turf D + DP X X

Trimec Classic

X (>) X (<) X

Trimec Southern

X (<) X (>) X

Phenoxy + Dicamba HerbicidesPhenoxy + Dicamba Herbicides

Herbicide 2,4-D MCPP MCPA 2,4-DP

dicamba

Triamine X X X

Triamine II X (>) X (<) X

Tri-Power X (<) X (>) X

Dissolve X X X

Triplet X (>) X (<) X (>)

Triplet Sens. X (<) X (>) X (<)

Phenoxy, Dicamba, Picolinic Phenoxy, Dicamba, Picolinic HerbicidesHerbicides

Herbicide 2,4-D

MCPA clopyralid

triclopyr

dicamba

Lontrel 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 GuidelinesPost 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 GuidelinesPost Herbicide Use Guidelines

Avoid 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 GuidelinesPost Herbicide Use Guidelines

Do 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 80°F.

Examples of Rain-Free PeriodsExamples of Rain-Free Periods

MSMA - 24 hoursTrimec Classic - 24 hoursBasagran T/O - 8 hoursFinale - 4 hoursVantage - 1 hour

Post Herbicide Use GuidelinesPost 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 potential

Apply to actively growing weeds - the cuticle is more easily penetrated

Sprays give better control than granules.

Post Herbicide Use GuidelinesPost 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 growing winter annual

lawn burweed

fruit

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

common chickweed

winter annual

winter annualsticky chickweed

henbithenbit

winter annual

Henbit

winter annual

Purple deadnettle

henbit

purple deadnettle

winter annuals

winter annual

hairy bittercress

fruit

winter annual shepherd’s purse

annual or biennial

purple cudweed

winter annual

parsley-piert

winter annual

seedling

corn speedwell

Virginia Virginia buttonweebuttonwee

dd

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.

Dandelion - PerennialDandelion - Perennial

2,4-D

Trimec

Confront

Drive

wild violet wild violet - -

perennialperennial

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

white clover - white clover - perennialperennial

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.

winter annual

Spotted burclover

Annual lespedeza

Summer annual

Chamberbitter, niruri

Summer 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 prostrate spurge - spurge - summer summer annualannual

Postemergence: Manor, Sencor, Trimec

Preemergence: Simazine, atrazine, Gallery

summer annual

fireweed

The 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 dollarweed

perennial

•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.

Dichondra, rhizomatous perennial

Controlled by repeat applications of atrazine, 30 days apart.

2 and 3-way growth regulator herbicides. Confront is a little better than Trimec related compounds.

perennial

ground ivy

buckhorn plantain

perennial

perennial

blackseed plantain

100% Control

Confront 2 pts/acre

Trimec 4 pts/acre

perennial

woodsorrel (Oxalis spp.)

Non-Target PlantsNon-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 ControlNonselective 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 Nonselective Broadleaf ControlControl

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 Lack of Post Herbicide PerformancePerformance

Environmental stressesWeed growth stageRain/irrigation wash-offNo adjuvantPoor spray coverage

Lack of Post Herbicide Lack of Post Herbicide PerformancePerformance

Wrong rateWrong herbicideNo follow-up applicationMowing effects