Postemergence

clethodim (Select or Prism)

Rate 0.094 to 0.125 lb ai/a (6 to 8 oz/a Select), depending on target weed species and growth stage.

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

Remarks Read label carefully for adjuvant instructions, and note effects of rain within 1 hour, application of other pesticides, and cultivation.

Caution See labels for maximum rates per application and season. Preharvest interval is 14 days.

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

Chemical family Cyclohexanedione

clopyralid (Stinger)

Spinach only

Rate Apply 0.063 to 0.124 lb ae/a (0.16 to 0.33 pints/a Stinger) with ground equipment in total spray volume of 10 gal/a or more.

Time Apply at the two- to five-leaf stage of spinach. Stinger controls wild buckwheat when applied in the one- to three-leaf stage of growth, before vining begins. Apply Stinger to clover from weed emergence up to the five-leaf stage of growth. To suppress sowthistle, apply Stinger from rosette up to bud stage.

Remarks Controls wild buckwheat, sweet clover, prickly lettuce, common ragweed, and galinsoga. Suppresses sowthistle.

Caution Preharvest interval is 21 days. Make one to two broadcast applications per crop per year, not to exceed 0.5 pint/a. Note crop rotational intervals on label.

Site of action Group 4: synthetic auxin

Chemical family Pyridine

imazamox (Raptor)

Chicory only

Rate 0.031 lb ae/a (4 oz/a Raptor)

Time Apply to chicory that has at least 2 and no more than 4 true expanded leaves when weeds are growing actively and less than 3 inches tall.

Remarks Add a nonionic surfactant or crop oil. Use of a nitrogen-based fertilizer will improve grass control but must be measured against the potential for increased crop injury.

Caution Apply grass herbicides before applying Raptor. Consult label for rotational crops and food or feed restrictions; this herbicide may persist for 26 months.

Site of action Group 2: acetolactate synthase (ALS) inhibitor (imazamox); Group 6: photosystem II inhibitor (bentazon)

Chemical family Imidazolinone and benzothiadiazole

pendimethalin (AquaPen 3.8)

Lettuce only; WA and ID only

Rate 1.0 lb ai/a (1.05 qts/a)

Time Broadcast when lettuce has 3 or more leaves.

Remarks Direct-seeded or transplanted lettuce. Preemergent weed control and will not control emerged weeds.

Caution Do not apply within 20 days of harvest and do not apply more than 1.05 quarts/year. Do not apply pre-plant, pre-transplant, or pre-emergence or severe injury will occur.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Dinitroaniline

phenmedipham (Spin-Aid)

Spinach only

Rate 0.49 to 0.98 lb ai/a (3 to 6 pints/a Spin-Aid)

Time Apply any time spinach is past four- to six-leaf stage and before weeds are at the two-leaf stage.

Remarks Avoid applying if weather may change rapidly from cool and cloudy to warm and sunny, or if spinach is stressed from insect, disease, or cultivation injury. Tip burn or temporary growth retardation and chlorosis may occur; plants usually recover within 10 days.

Caution Restricted-use herbicide. Preharvest interval is 40 days. Avoid diluting herbicide more than 1 quart to 7 gal water in spray tank, which can cause the chemical to precipitate.

Site of action Group 5: photosystem II inhibitor

Chemical family Phenylcarbamate

sethoxydim (Poast)

Rate 0.188 to 0.28 lb ai/a (1 to 1.5 pints/a Poast)

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 temperatures, or low fertility. Resistant grasses include annual bluegrass and all fine fescues, but quackgrass can be suppressed. Inhibits fatty acid production, cell membranes, and new growth.

Caution Preharvest interval is 15 days for spinach and leaf lettuce, 30 days for head lettuce. Do not exceed 3 pints/a per season. Avoid applying when temperatures exceed 90°F or when relative humidity exceeds 60%.

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

Chemical family Cyclohexanedione

triflusulfuron methyl (UpBeet)

Supplemental labels in the PNW for endive and chicory only

Rate 0.0156 lb ai/a (0.5 oz/a UpBeet)

Time Apply when endive or chicory plants have developed one true leaf (two cotyledons and one true leaf). Use at least two sequential applications for best results. Apply 5 to 10 days apart, depending on weed size.

Remarks Apply to small, actively growing weeds. Nonionic surfactants may be used at 0.25% v/v but may increase risk of crop injury. Crop oil concentrates are not recommended. Controls pigweed, kochia, shepherdspurse, and velvetleaf.

Caution Discoloration may be noted in some cases but effects are temporary. Do not contaminate water bodies, or rinse or flush spray near roots of trees and desirable plants, or injury may result.

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

Chemical family Sulfonylurea