Established Plantings-Burndown and Directed Applications in or between Berry Rows without Soil Residual

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. Application equipment must be hooded or shielded. Any contact with the crop will cause crop injury. Weed Pharm can be applied up to and including the day of harvest. Approved for organic production.

Caution This product is a contact, nonselective, herbicide. Avoid contact with desirable foliage, green bark, or fruit. Causes irreversible eye damage. Wear goggles or face shield.

bentazon (Basagran)

Non-bearing, blueberry only

Rate 0.75 to 1 lb ai/a (1.5 to 2 pints/a Basagran)

Time Spring to early summer, depending on growth stage of weeds.

Remarks Supplemental label (Arysta LifeSciences) for nonbearing crops. Useful for suppression and control of yellow nutsedge, Canada thistle, and musk thistle. For Canada thistle apply 2 pints/a when plants are between 8 inches tall and bud stage. Apply a second application 10 to 12 days later if needed. For nutsedge, apply 1.5 to 2 pints/a when plants are 6-8 in tall, and make a second application 7 to 10 days later if needed. Always add a crop oil concentrate. Use no more than 2 lb ai/a per year. Irrigate to make sure plants are actively growing before applying bentazon. Do not cultivate or mow for 5 days after application. Weeds growing under drought conditions may not be adequately controlled.

Caution Apply as a directed spray, away from the crop. Do not allow contact with foliage. Do not apply within one year of crop harvest.

Site of action Group 6: photosystem II inhibitor

Chemical family Benzothiadiazole

carfentrazone (Aim)

Hooded spray between rows

Rate 0.016 to 0.031 lb ai/a (1 to 2 fl oz/a product in at least 10 gal/a water)

Time Apply to weeds less than 4 inches tall for best results.

Remarks Apply with hooded sprayers between rows at speeds less than 5 mph. Use nonionic surfactants, crop oil concentrates, or methylated seed oils combined with liquid nitrogen fertilizer to improve efficacy. Aim can be applied up to and including the day of harvest.

Caution Must prevent spray from contacting green stem tissue, foliage, blooms, or fruit. Hooded sprayers must totally enclose the spray pattern. Newly planted fields should be treated with shielded sprayers.

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

Chemical family Triazinone

clethodim (Select Max, Arrow, and others)

Rate 0.07 to 0.12 lb ai/a (9 to 16 fl oz/a Select Max for annual grasses; 12 to 16 oz/a Select Max for perennial grasses) See label for rates of other products.

Time Apply to actively growing grass weeds, including annual bluegrass, at labeled growth stage.

Remarks Preharvest interval is 14 days. Read label carefully for adjuvant instructions, and for information about effects of rain within 1 hour, applications of other pesticides, or cultivation. Minimum of 14 days between applications.

Caution Do not broadcast spray. Direct spray at base of the plant where grassy weeds are growing. Do not exceed 64 fl oz/a Select Max or 32.0 fl oz/a Arrow per season.

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

Chemical family Cyclohexanedione

fluazifop (Fusilade DX)

Rate 0.25 to 0.38 lb ai/a (16 to 24 oz/a Fusilade DX) depending on target weed species

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 Identify grasses and adjust rates depending on susceptibility and stage of weed 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. Annual bluegrass and all fine fescues resist treatment. Inhibits fatty acid production, cell membranes, and new growth.

Caution Preharvest interval is 1 day. Grazing is prohibited.

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

Chemical family Aryloxyphenoxy propionate

glufosinate (Rely 280, Lifeline, and other brands)

Rate 0.88 to 1.5 lb ai/a (1.5 to 2.5 quarts/a Rely 280) depending on target weed species and size

Time Apply to small, actively growing weeds

Remarks Apply as a directed spray to weeds, avoiding contact with blueberry foliage. Avoid direct spray or drift to desirable vegetation.

Caution Do not apply to green bark on young bushes, or injury will occur. Do not allow glufosinate to contact new emerging shoots. Do not exceed 3 lb ai/a of glufosinate (5.1 quarts/a ) to berry bushes in a 12-month period. Preharvest interval is 14 days.

Site of action Group 10: inhibits glutamine synthase

Chemical family Phosphinic acid

glyphosate (several products)

Rate Broadcast or directed spray: Consult labels

Remarks Select application equipment to prevent crop injury by directing spray or by using selective applicators. Adjust concentration depending on equipment. Consult label about rate and time of application, especially for perennial weeds. Additional surfactant, or mixing ammonium sulfate as label instructs, may improve control of slightly stressed weeds. Inhibits production of three amino acids and protein synthesis. Preharvest interval is 14 days.

Caution Do not allow drift or mist to contact green foliage or bark, suckers, or vines and renewals less than 3 years old. When repeat applications are necessary, do not exceed 10.6 lb ai/a per year. Repeated glyphosate applications have created resistant biotypes of annual ryegrass in Oregon orchards. To avoid weed resistance, rotate and mix weed control practices.

Site of action Group 9: inhibits EPSP synthase

Chemical family None generally accepted

glyphosate (several products)

Rate Wiper: 33% solution

Time Apply 1 gal product with 2 gal water and wipe weeds; avoid contact with desirable vegetation.

Remarks In severe infestations, reduce equipment ground speed or apply in two directions to ensure contact with wiper. (See remarks above.) Preharvest interval is 14 days.

Site of action Group 9: inhibits EPSP synthase

Chemical family None generally accepted

paraquat (Gramoxone SL 2.0)

Rate 0.625 to 1 lb ai/a (2.5 to 4 pints/a Gramoxone SL 2.0)

Time Apply up to 5 times per season as a directed spray toward plant base; ensure complete wetting when weeds are small. Avoid spray contact with foliage a new shoots.

Remarks Add a nonionic surfactant or crop oil concentrate as label specifies; take care to avoid anionic formulations that react in the tank to form insoluble precipitates. Acts on contact; absorbs energy produced by photosynthesis, forming peroxides that disrupt living cells.

Caution A restricted-use herbicide. Do not ingest or inhale spray mist. Wear protective shields, respirators, and clothing. Do not let spray contact foliage, fruit, or young tree trunks. Do not graze treated areas.

Site of action Group 22: photosystem I electron diversion

Chemical family Bipyridilium

pelargonic acid (Scythe)

Rate For annual weeds, a 3 to 5% solution; for burndown or sucker control, a 5 to 7% solution

Time Apply in 75 to 200 gal/a water broadcast when temperatures exceed 45°F. Apply to weeds or primocanes shorter than 6 inches.

Remarks Cool weather after treatment may slow activity and delay or reduce visible effects. Adding a surfactant may enhance control. Preharvest interval is 1 day.

Site of action Unknown

Chemical family Unknown

sethoxydim (Poast)

Blueberry only

Rate 0.19 to 0.47 lb ai/a (1 to 2.5 pints/a Poast) depending on target weed species

Time Identify susceptible grasses and apply at optimum growth stage listed on label.

Remarks 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. Preharvest interval is 30 days.

Caution Do not exceed 5 pints/a per season.

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

Chemical family Cyclohexanedione