Weed Management Handbook

NONSELECTIVE POSTEMERGENCE

glufosinate (Cheetah Pro EPA# 228-743)

Rate Apply at 24 - 82 fl oz/A. Use higher rates when weeds are more mature. Use higher rates when controlling annual bluegrass and other grasses.

Time Apply when target plants are actively growing.

Old turf areas eventually are invaded and often dominated by naturalized grasses including bentgrasses, roughstalk bluegrass, annual bluegrass, velvetgrass, tall fescue, quackgrass, and bermudagrass. Managers who desire pure turf stands need to renovate periodically by killing all vegetation and reseeding.

PREEMERGENCE

bensulide (GORDONS PRO T&O PROD BENSUMEC 4 LF EPA# 2217-696)

Rate 6.25 gal (50 pints)/A or 18 fl oz of Bensumec 4LF/1,000 sq ft.

Time Apply to established turfgrasses on golf courses only.

Summer annual grasses are rarely a problem in western Washington, or in the Willamette Valley and coastal areas of Oregon. They may be a problem in areas east of the Cascades throughout the Northwest and south of the Willamette Valley in Oregon, depending on local conditions. In controlling annual grasses, it is important to positively identify the grass before acting, to avoid wasting time and chemicals treating perennial grasses.

bentazon (NON-Homeowner BASAGRAN T&O HERBICIDE EPA# 7969-326)

Rate 2 pints/A in 40 to 80 gal water or 0.75 fl oz/1,000 sq ft in 1 to 2 gal water. Second application in 70 to 10 days.

Time Apply to actively growing weeds.

SELECTIVE PREEMERGENCE

See preemergence herbicides listed for annual grasses.

SELECTIVE POSTEMERGENCE

amicarbazone (Xonerate Herbicide EPA#66330-46)

Oregon only

Rate 3 to 29 fl oz/A Xonerate (See label for specific turfgrass rates and recommendations) Per label: 1.0 to 10.0 oz/A

Selective control of annual bluegrass in turf is a big challenge in the Pacific Northwest. There are no tried-and-true procedures. Every breakthrough reported in another region of the United States is less effective in the PNW than in climates with greater environmental stress. Current strategies involve selective preemergence herbicides, selective pre- and early postemergence herbicides, and selectively suppressing growth with turfgrass growth regulators.

2,4-D + triclopyr (Turflon D Low Volatile Weed Killer EPA#62719-67; Chaser Turf Herbicide EPA#34704-928; Chaser 2 Amine EPA#34704-930; CONFRONT SPECIALTY HERBICIDE EPA# 62719-92)

For use on golf courses only

2,4-D + fluroxypyr + halauxifen-methyl (GAMEON SPECIALTY HERBICIDE EPA# 62719-724)

Rate 3 to 4 pints per acre. Do not reapply within 3 weeks of a previous application. Do not exceed 8 pints per acre annually.

Mixing two or more herbicides can dramatically increase the spectrum of weed control. Most mixtures have a wide safety margin on desirable grasses and some are specially formulated for sensitive grasses such as bentgrass. Mixtures generally are available in amine salt and low-volatile ester formulations. Ester formulations are the materials of choice in early spring, late fall, and during rainy weather. Amine salt formulations generally are safer than esters around nontarget plants and during period of warm weather.