Herbicides for Large Food Gardens—Professional Use

Multiply rate by 0.023 for amount per 1,000 sq ft

LARGE FOOD GARDENS—Preemergence, Soil-applied Treatments

napropamide (Devrinol 2G Ornamental)

Fruits and nuts

Rate 4 to 6 lb ai/A

Time Apply to weed-free soil any time of year, although fall and winter applications are preferred.

Remarks Use higher rates for dense infestations containing many annual broadleaf weeds. Incorporate evenly in the top 1 to 2 inches of soil or irrigate within 2 to 3 days for best control.

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

Chemical family Acetamide

trifluralin (Treflan EC)

Certain vegetables

Rate Consult label for rates on various vegetables, usually 0.5 to 0.75 lb ai/A (1 to 1.5 pints/A)

Time Preplant-incorporate before seeding or transplanting vegetables.

Remarks Note herbicide rates for soil types and crop groupings. Incorporate herbicide uniformly in the top 2 to 3 inches of soil to reduce evaporation of the product. Do not overapply.

Caution Do not apply to sweet corn or to direct-seeded cucurbits, because serious injury may occur.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Dinitroaniline

LARGE FOOD GARDENS—Postemergence, Directed or Foliar-applied Treatments for Vegetables, Trees, and Nuts

acetic acid (Weed Pharm 20%)

Rate Undiluted

Time Apply when weeds are small, at the 3 to 5 leaf stage, and actively growing.

Remarks Apply before crop emergence, or between rows after emergence, avoiding contact with desirable foliage. Directed sprays or hooded sprayers are recommended. Works best if applied in direct sunlight when temperatures are above 65°F. Approved for organic production.

Caution Contact with foliage of desirable plants will cause damage. Use nozzles that reduce spray drift. Corrosive; causes irreversible eye damage.

clove leaf oil (Matran EC)

Rate 5 to 8% dilution in 25 to 100 gal of water, depending on weed size, temperature, and sunlight intensity.

Time Before weeds are 6 inches tall.

Remarks OMRI-listed and WSDA-approved herbicide for in-crop use. Apply before crop emergence, or between rows after emergence, avoiding contact with desirable foliage. Directed sprays or hooded sprayers are recommended. Works best on annual weeds less than 6 inches. Performance may be erratic depending on environmental conditions. Bright sunlight improves efficacy. No preharvest interval or reentry interval.

glyphosate (several products)

Rate Consult labels

Time Apply as a spray, spot treatment, or wiper application to actively growing weeds at least 7 days before planting vegetables and labeled tree or nut crops.

Remarks Note all precautions, correct time of application for maximum weed control, and restrictions involving preplant application and preharvest intervals.

Caution Apply only to crops listed on the label.

Site of action Group 9: inhibits EPSP synthase

Chemical family None generally accepted

lemongrass oil (Green Match EX)

Rate 7 to 15% depending on weed size and species.

Time When weeds are less than 6 inches tall.

Remarks OMRI-listed, NOP-compliant, and WSDA-approved organic burndown herbicide for use in crop and non-crop sites. Green Match will damage foliage on contact; leaf damage is visible within hours. Directed sprays or hooded sprayers are recommended. Coverage is very important. Cool weather may slow activity. No reentry interval. Fast wilting or necrosis of the leaves due to removal of waxy cuticle.

sethoxydim (Poast)

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

Time Apply at optimum growth stage listed on the label.

Remarks Labeled for use on many vegetable crops. 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, heat, 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 Preharvest interval for some vegetables may be as long as 60 days. Apply only to listed vegetable crops.

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

Chemical family Cyclohexanedione