clethodim (Select Max, Envoy, and others)
Nonbearing crop only
Rate 0.068 to 0.121 lb ai/a (9 to 16 fl oz/a Prism)
Time Apply to actively growing grass weeds, including annual bluegrass, at growth stage listed on label.
Remarks Read label carefully for adjuvant instructions and for information about effects of rain within 1 hour, applications of other pesticides, or cultivation. Do not apply to a vine that will bear fruit in 1 year after Prism application.
Caution Do not exceed 68 fl oz/a per season.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Aryloxyphenoxy propionate
diquat (Reglone)
Nonbearing only
Rate 0.375 to 0.5 lb ai/a (24 to 32 fl oz/a)
Time Apply to completely cover rapidly growing weed foliage, to facilitate planting. Add a nonionic surfactant.
Site of action Group 22: photosystem I electron diversion
Chemical family Bipyridilium
fluazifop (Fusilade DX)
Rate 0.25 to 0.375 lb ai/a (16 to 24 oz/a Fusilade) Refer to specific grassy weeds on label
Time Apply to actively growing grasses, or within 7 days after irrigation, as a directed spray with 1% crop oil or 0.25% nonionic surfactant.
Remarks Labeled on bearing grapes. Identify grass weeds and adjust rates, depending on susceptibility and stage of growth, as label instructs. Results often are erratic on grasses stressed from lack of vigor, drought, high temperature, or low fertility. More mature grasses and quackgrass can be controlled but may require two applications. Do not apply more than 24 fl oz/a/ application or more than 72 oz/a/year. Annual bluegrass and all fine fescues resist treatment. Do not apply twice within 14 days. Use recommended adjuvants.
Caution Preharvest interval is 50 days. Grazing is prohibited.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Aryloxyphenoxy propionate
glyphosate (numerous product names)
Rate 0.47 to 4.5 lb ai/a (11 oz to 3.3 quarts/a Roundup Power Max)
Time Apply to actively growing weeds either as site preparation or in nonbearing crops 1 year before first harvest.
Remarks Avoid contact with green crop foliage or suckers.
Caution Do not exceed 8 lb ae/a per year. Follow all precautions on label. Repeated glyphosate applications have selected for resistant biotypes of ryegrass in the PNW. To avoid weed resistance, rotate and mix weed control practices.
Site of action Group 9: inhibits EPSP synthase
Chemical family None generally accepted
sethoxydim (Poast)
Rate 0.19 to 0.47 lb ai/a (1 to 2.5 pints/a Poast)
Time Add 2 pints/a of a nonphytotoxic crop oil concentrate to improve leaf absorption.
Remarks Identify susceptible grasses and apply at optimum growth stage listed on label. Control often is erratic on grasses stunted or stressed from drought, high temperatures, or low fertility. Resistant grasses include annual bluegrass and all fine fescues; quackgrass can be suppressed.
Caution Preharvest interval is 50 days. Do not exceed 5 pints/a per season.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Aryloxyphenoxy propionate