Established Plantings-Weed Control during Bed Renovation in Summer

Cultivation After harvest, withhold irrigation to induce "summer dormancy" in strawberries before treating perennial weeds. Cultivate row middles to reduce runners and control weeds.

2,4-D (Formula 40 and others)

Rate 0.9 to 1.4 lb ae/a (1 to 1.5 quarts/a Formula 40)

Time Apply immediately after last harvest, in 20 to 25 gal/a water.

Remarks Make sure the label includes strawberries, and follow directions carefully. Triple-rinse and wash spray tank with appropriate cleaners before applying herbicides to other crops.

Caution Do not use unless possible crop injury is acceptable. Avoid use under conditions that favor drift or movement to susceptible crops.

Site of action Group 4: synthetic auxin

Chemical family Phenoxy acetic acid

acetic acid (Weed Pharm Weed and Grass Killer)

Rate 15 to 30 gal product/a

Remarks 20% acetic acid. Apply as a directed application to actively growing small weeds in row middles only. Use application equipment that is hooded or shielded. Any contact with the crop will cause crop injury. Approved for organic production.

Caution This product is a contact, nonselective, herbicide. Avoid contact with desirable foliage, green bark, or fruit.

carfentrazone-ethyl (Aim EC)

Rate Apply only to row middles at rates up to 0.031 lb ai/a (2 fl oz/a Aim EC) broadcast per application in at least 10 gal/a of finished spray. See label for rate based on target weed species.

Time Apply postemergence to actively growing broadleaf weeds, as listed on label.

Remarks Controls listed broadleaf weeds up to 4 inches tall. Will not control grass weeds. A nonionic surfactant, methylated seed oil, or crop oil concentrate is required. Consult label for adjuvant selection and instructions.

Caution Apply only to row middles, using a shielded or hooded sprayer that prevents any spray from contacting strawberry plant tissues. Crop will be injured if spray contacts green stem tissues, leaves, blooms, or fruit. See label for hooded or shielded sprayer directions. Do not exceed 6.1 fl oz/a broadcast (0.096 lb ai/a) per season as a row-middle application.

Site of action Group 14: inhibits protoporphyrinogen oxidase (PPO)

Chemical family Triazolinone

clethodim (Select 2EC and others)

Rate 0.09 to 0.125 lb ai/a (6 to 8 oz/a Select 2EC)

Time Apply to actively growing grasses at recommended weed heights.

Remarks Add crop oil concentrate as described on label.

Caution Do not exceed 8 fl oz/a per treatment or 32 fl oz/a per season.

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

Chemical family Cyclohexanedione

napropamide (Devrinol 2-XT, Devrinol DF-XT)

Rate 4 lb ai/a (8 quarts/a Devrinol 2-XT, 8 lb/a Devrinol DF-XT)

Time Apply to weed-free soil after bed renovation.

Remarks Prevents daughter plants from rooting.

Caution Do not exceed 4 lb ai/a per year. Inhibits root growth.

Site of action Group 15: inhibits very-long-chain fatty acid synthesis

Chemical family Acetamide

paraquat (Gramoxone Inteon)

Rate 0.5 lb ai/a (2 pints Gramoxone Inteon/a)

Time Apply as a directed spray between rows, using shields to prevent spray contact with crop.

Remarks Add nonionic surfactant or crop oil concentrate as label directs; avoid anionic formulations that react to form insoluble precipitates. Acts as contact; absorbs energy produced by photosynthesis, forming peroxides that disrupt living cells.

Caution A restricted-use herbicide. Do not inhale or ingest spray mist. Wear protective face shields, respirators, and clothing. Do not exceed three applications a year. Preharvest interval is 21 days.

Site of action Group 22: photosystem I electron diversion

Chemical family Bipyridilium

pendimethalin (Prowl H2O)

Rate 0.71 to 1.4 lb ai/a (1.5 to 3 pints/a Prowl H2O)

Time During renovation when no foliage is exposed.

Caution Do not apply if new leaves have emerged or are exposed. Stunting, reduced growth, or reduction in daughter plants may result. Refer to main labels for crop rotation restrictions.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Dinitroaniline

sethoxydim (Poast)

Rate 0.47 lb ai/a (2.5 pints/a)

Time Apply at optimum growth stage listed on label.

Remarks Identify susceptible grasses; add 2 pints/a of 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; quackgrass can be suppressed. Inhibits fatty acid production, cell membranes, and new growth.

Caution Do not exceed 2.5 pints/a per season. Note special precautions on Sinbar applications based on crop injury experienced in other regions; never tank mix Sinbar with Poast; wait at least 2 weeks between applying these herbicides.

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

Chemical family Cyclohexanedione

simazine (Princep 4L)

Oregon and Washington only

Rate 1 lb ai/a (1 quart/a Princep 4L)

Time Apply after bed renovation and first irrigation followed with additional 0.5 inch irrigation to activate the herbicide. Apply only once per year.

Remarks In summer, simazine is only about half as active as in winter applications.

Caution Do not apply on sandy soils.

Site of action Group 5: photosystem II inhibitor

Chemical family Triazine

sulfentrazone (Spartan 4F)

Rate 0.125 to 0.25 lb ai/a (4 to 8 oz/a Spartan)

Time Apply after harvest, and after mowing at bed renovation.

Remarks Strawberries are listed on the federal Spartan 4F label but Oregon and Washington SLN labels (OR-110009 and WA-110007) provide use pattern and directions more appropriate to Oregon and Washington production systems. Water is required to activate sulfentrazone.

Caution Avoid contact with newly emerged strawberry growth, as leaf burning and stand loss may occur. Do not exceed 0.25 lb ai/a (8 oz/a) per application, or a maximum of 0.375 lb ai/a (12 oz/a) per season. Do not use on coarse, sandy soils with less than 1% organic matter. For use only by those certified and/or licensed as pesticide applicators.

Site of action Group 14: inhibits protoporphyrinogen oxidase (PPO)

Chemical family Triazolinone

terbacil (Sinbar)

Rate 0.2 to 0.4 lb ai/a (4 to 8 oz/a Sinbar)

Time Apply to strawberries established at least 6 months.

Remarks Avoid use for 2 years if replanting is planned; consult label for recropping information. Split applications at lower rates are preferred after bed renovation in summer, before new strawberry growth begins, and before weeds are more than 2 inches tall or wide.

Caution Do not exceed 0.4 lb ai/a (8 oz/a per year) or use on sandy, loamy sands, gravelly soils, or soils with less than 2% organic matter. Inhibits photosynthesis.

Site of action Group 5: photosystem II inhibitor

Chemical family Uracil