2,4-D low-volatile ester (Riverdale 2,4-D Granules)
Rate 2 to 4 lb ae/A (10 to 20 lb/A product)
Time Apply in early spring, while cranberries are dormant and leaves are completely dry.
Remarks Use higher rates as spot treatments on certain perennial weeds only; use lower rates in combination with other herbicides. Early winter applications may be effective against several broadleaf biennial species. Mimics natural plant hormones. Avoid contact with vines.
Site of action Group 4: synthetic auxin
Chemical family Phenoxy acetic acid
chlorimuron (Curio)
Rate 0.008 to 0.016 lb ai/A (Washington: 0.5 to 1 oz/A, Oregon: 0.5 oz/A product)
Time Apply any time after March 1 but no later than 60 days before harvest. Use lower rate (0.5 oz/A) from the hook stage of development to bud set.
Remarks Requires waiver of liability signature prior to use. Controls creeping buttercup and several other perennial weeds. Optimal control of creeping buttercup can be achieved from a March to April timing. Requires the use of a spray adjuvant. SLN labels: WA-100004 and OR-120001.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
carfentrazone-ethyl (Aim EC)
Rate 0.031 lb ai/A (2 oz/A product)
Time Dormant application only. Spot applications recommended. Chemigation is not allowed.
Remarks This is a non-selective contact herbicide with no systemic action. An adjuvant is required; see label for details.
Site of action Group E: protoporphyrinogen oxidase inhibitor
Chemical family Aryl triazolinone
clethodim (Select Max and several trade names)
Rate 0.068 to 0.121 lb ai/A (9 to 16 oz/A)
Time Apply to actively growing grasses, including annual bluegrass, at growth stage listed on label using 0.5% to 1% nonphytotoxic crop oil or 0.25% nonionic surfactant. Preharvest interval is 30 days.
Remarks On label, carefully read about adjuvants, effects of rain within 1 hour, application of other pesticides, and cultivation. Intensity and Intensity One have Special Local Needs (SLN) labels: WA-180004 and WA-180005, for chemigation application. Vaquero has a SLN label for chemigation in Oregon: OR-190014.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitors
Chemical family Cyclohexanedione
clopyralid (Stinger)
Rate 0.09 to 0.25 lb ai/A (0.25 to 0.66 pints/A product)
Time Apply only when cranberries are not actively growing. This begins when cranberry vines go dormant in late fall and ends with budbreak. The second application period is after fruit set, up to 60 days before harvest.
Remarks Vines growing under the weed canopy may be sensitive to Stinger. Avoid contact with vines. Identify susceptible weed species (legume and composite families), and apply postemergence when weed canopy becomes visible. Results are best when applied before weeds mature. Do not exceed 0.67 pint/A per season. Do not add surfactant or crop oil. Special local needs labels WA-030006 and OR-030009.
Site of action Group 4: synthetic auxin
Chemical family Pyridine
dichlobenil (Casoron 4G)
Rate 1.2 to 4 lb ai/A (30 to 100 lb/A product)
Time Apply from midwinter to early spring, before bud break.
Remarks Results on sandy soils usually are best with split applications in midwinter to early spring. Allow 3 to 6 weeks between treatments. Do not exceed 4 lb ai/A (100 lb/A) total per year. Irrigation or rain should follow applications to minimize vaporization and loss of chemical. Use higher rates only on very weedy beds and organic soils. Plants will temporarily redden after spring applications.
Caution Do not apply at or beyond popcorn stage, or on newly sanded or new beds. Injury may occur where applications overlap or where water stands in low wet areas. Use lower rates (1.2 to 2.3 lb ai/A) on soils low in organic matter. Continued use at medium to high rates on sandier soils will result in a gradual but significant decline in production and plant health. Sanding is recommended to remediate the negative impacts of long term use of dichlobenil.
Site of action Group 20: inhibits cell wall synthesis Site A
Chemical family Nitrile
mesotrione (Callisto and several trade names)
Rate Up to 0.25 lb ai/A (up to 8 oz/A product)
Time Apply only after budbreak but less than 45 days before flooding.
Remarks Use with a nonionic surfactant at 0.25% v/v or crop oil at 1% v/v as recommended by the label. Callisto may be applied in cranberries at a rate up to 8 fl oz/A. Do not exceed 16 fl oz/A or two applications per year. Allow at least 14 days between treatments. Callisto may be applied through irrigation systems (chemigation) including center pivot or solid set.
Caution Avoid using crop oils that injure cranberry vines.
Site of action Group 28: inhibits 4-hydroxyphenylpyruvatedioxygenase (4-HPPD)
Chemical family Triketone
napropamide (Devrinol DF-XT, 2-XT)
Rate Sand beds: 4 to 9 lb ai/A (8 to 18 lb/A of DF 2-XT formulation); Peat beds: 6 to 9 lb ai/A (12 to 18 lb/A of DF-XT formulation)
Time Apply before weeds begin to germinate and before spring growth begins, in mid-February to mid-March.
Remarks Requires ample rain or irrigation to activate. On 1-year-old beds, use lower rates. Crop may be injured at high rates. Control may lessen with repeated use. Inhibits root and shoot growth. Devrinol may be applied through the sprinkler irrigation systems.
Caution Do not apply after buds begin to swell.
Site of action Group 15: inhibits very long chain fatty acid synthesis
Chemical family Acetamide
norflurazon (Evital 5G)
Rate 4 to 8 lb ai/A (80 to 160 lb/A product)
Time Apply midwinter to early spring, before new growth begins.
Remarks Use lower rates not exceeding 3 lb ai/A on: sandy soils low in organic matter; on sensitive hybrid varieties such as 'Stevens,' 'Pilgrim,' or 'Crimson Queen' PP #18,252; on young plants; or on beds with weak vines. Higher rates are required on older beds with higher organic content. Some growers and researchers report reduced crop yields when the product is applied in consecutive years, especially with new hybrids. Injury may occur if applications overlap, or if water stands in low, wet areas. Use lower rates and alternate with other herbicides to reduce possibility of injury.
Site of action Group 12: bleaching; inhibits carotenoid biosynthesis
Chemical family Pyridazinone
quinclorac (Quinstar 4L)
Rate Up to 0.25 ai/A (8.4 oz/A product)
Time Quinstar 4L is most effective on actively growing cranberry weeds listed on the label, when applied at the early postemergence stage of development.
Remarks Apply as a foliar application using a crop oil concentrate at a rate of 2 pints/A. A second application may be made at least 30 days after the first application. Do not exceed two applications per year. Quinstar 4L may also be applied with chemigation. Prior to application, consult your handler for MRL restrictions on export fruit.
Site of action Group 4: synthetic auxin
Chemical family Quinoline carboxylic acid
sethoxydim (Poast and several trade names)
Rate Spray: 0.28 to 0.47 lb ai/A (1.5 to 2.5 pints/A product). Spot treat: 2 oz or 4 Tbsp/gal water + 2.5 oz or 4 Tbsp crop oil concentrate
Time Apply at optimum growth stage listed on the label. Preharvest interval is 60 days.
Remarks Identify susceptible grasses and 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. Inhibits fatty acid production, cell membranes, and new growth.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitors
Chemical family Cyclohexanedione
sulfentrazone (Antares)
Rate 0.125 to 0.375 lb ai/A (4 to 12 oz/A product)
Remarks Applied broadcast to berry beds and furrows or banded to the base of berries. Chemigation is not allowed. Do not exceed 12 oz/A per 12-month period. Make application only to berry bushes that have been established for a full growing season, and are healthy. Spray solution should not be allowed to contact green bark of young bushes. Protect green bark from spray solution with a grow tube, wax container or nonporous wrap. Make sure that spray does not contact foliage or fruit, and when applying after petal fall, use a shielded or hooded sprayer
Site of action Group 14: Protoporphyrinogen oxidase inhibitor
Chemical family N-Phenyl-triazolinones