Postemergence

clethodim (Prism or Select)

Rate For tomatoes, 0.094 to 0.188 lb ai/a (6 to 12 oz/a Select); for peppers and eggplants, 0.094 to 0.125 lb ai/a (6 to 8 oz/a Select). Also depends on weed growth stage.

Time Apply to actively growing grass weeds, including annual bluegrass, at growth stage as on label.

Remarks Consult labels for maximum rates per application and season. Read label carefully for adjuvant instructions and for information about effects of rain within 1 hour, applications of other pesticides, and cultivation. Preharvest interval is 20 days.

Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor

Chemical family Cyclohexanedione

halosulfuron (Sandea)

Consult label for crop-specific instructions

Rate 0.023 to 0.047 lb ai/a (0.5 to 1 oz/a)

Time Tomatoes: Apply broadcast to actively growing transplanted tomatoes with four leaves or more, 14 days or more after transplanting, but before first bloom. May also be used as spot treatment when weeds have broken through plastic mulch. Eggplant and pepper: apply to row middles or furrows only, avoiding herbicide contact with the planted crop.

Remarks Repeat application may be required to control nightshade species, but do not exceed 2 applications (2 oz/a Sandea) per year.

Caution Observe crop rotation restrictions carefully.

Site of action Group 2: acetolactate synthase (ALS) inhibitor

Chemical family Sulfonylurea

metribuzin (Tricor 4F)

Tomatoes only, must be established

Rate 0.25 to 0.5 lb ai/a (0.5 to 1 pint/a)

Time Apply postemergence as a single treatment or a split application, with at least a 14-day interval, to tomatoes with at least five to six true leaves, but before weeds are 1 inch tall.

Remarks Use lower rates on soils with 0.5% to 2% organic matter, but do not use on soils with less than 0.5% organic matter. Up to 2 pints/a can be applied if application is directed and spray does not contact foliage. Inhibits photosynthesis.

Caution Do not use surfactant or tank mix with other pesticides. Do not apply within 24 hours of other pesticide applications. Preharvest interval is 7 days. Do not apply within 3 days after cool, wet, or cloudy weather. Do not exceed 1 lb ai/a per season. Carefully note other precautions on label. Does not control nightshade or other related weeds

Site of action Group 5: photosystem II inhibitor

Chemical family Triazinone

paraquat (Gramoxone Inteon, 2 lb paraquat cation/gal)

Rate Preplant and preemergence: 0.5 to 1 lb ai/a cation (2 to 4 pints/a Inteon). Postemergence directed: 0.5 lb ai/a cation (2 pints/a Inteon).

Time Apply as a directed spray between rows after crop is established, but before emerged weeds reach 6 inches tall.

Caution A restricted-use herbicide due to acute toxicity. Do not exceed three applications per season. Preharvest interval is 30 days. Do not graze animals.

Site of action Group 22: photosystem I electron diversion

Chemical family Bipyridilium

rimsulfuron (Matrix)

Field-grown tomatoes only

Rate 0.25 to 0.5 oz ai/a (1 to 2 oz/a) postemergence

Time Apply when weeds are less than 1 inch tall or wide and crop is at the cotyledon stage.

Remarks Use a nonionic surfactant at 0.25% v/v. Sequential applications 7 to 14 days apart may improve black nightshade control. Tomato varieties may differ in tolerance to rimsulfuron; apply to a small test area before treating whole fields.

Caution Using adjuvants at more than 0.25% v/v may result in temporary chlorosis. Consult labels for rotational intervals. Preharvest interval is 45 days.

Site of action Group 2: acetolactate synthase (ALS) inhibitor

Chemical family Sulfonylurea

sethoxydim (Poast)

Rate 0.28 lb ai/a (1.5 pints/a)

Time Apply at optimum growth stage listed on the label.

Remarks Identify susceptible grasses and add 2 pints/a nonphytotoxic crop oil concentrate to improve leaf absorption. Control often is erratic on grasses stunted or stressed from drought, high heat, or low fertility. Resistant grasses include annual bluegrass and all fine fescues; quackgrass can be suppressed.

Caution Preharvest interval is 20 days. Do not exceed 4.5 pints/a per season. Inhibits fatty acid production, cell membranes, and new growth.

Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor

Chemical family Cyclohexanedione