Strawberries

Joe DeFrancesco
Revised March 2014

Weed control practices in strawberries must be timed to coincide with the crop’s non-reproductive phases, or when minimal herbicide uptake can be expected. Strawberries can be induced into a non-reproductive “summer dormancy” by withholding water and fertilizer after harvest. Beds can be renovated by mowing old leaves, cultivating row middles, and sometimes by applying a herbicide. In mid-August, plants are fertilized and watered to enhance flower bud development. Soil-applied herbicides can be applied at full rates in the fall. Sometimes, a foliar-active herbicide can be applied during the “summer” or “winter” dormancy when plants are completely inactive, if the grower is willing to accept the risk of crop injury.

Weed shifts Although strawberries are rotated with other crops every 2 to 4 years, some weed species may persist or increase with repeated use of the same or similar weed control practices, causing shifts in weed populations. Examples include deep-rooted perennials that survive cultivation, or weeds such as common groundsel that either resist the herbicide or are selected from a natural population of susceptible biotypes.

Preventing weed shifts Weeds that survive cultivation, specific herbicide treatments, or other routine cultural practices must be eliminated before the tolerant species or biotypes become established. Combine a variety of weed control practices or treatments, rotate practices and herbicides, and spot-treat with a hoe or registered herbicide when a new weed first appears. Also, clean equipment when moving from an infested field.

Managing weeds in strawberry fields Successful weed control in strawberry fields requires a comprehensive or year-round approach employing and alternating a combination of weed control practices over several years. Developing these strategies requires knowledge of each weed and weed control practice. Weeds must be identified and information gathered about the effectiveness of each weed control practice. Consider costs and select herbicide combinations that can be applied together or in split applications that control the weeds in the field. Note the action of each herbicide or how the chemical works in the plant. Then tank-mix and alternate use of these products to reduce the chance of developing resistant species or biotypes. Often, a combination of mechanical methods, herbicide treatments, and sometimes hand removal or spot treatment with herbicide sprays will provide the most effective year-round control.

Managing soil erosion Band treatments of soil-active herbicides within the row. Planting annual cover crops such as spring barley or oats in row middles reduces water runoff and soil erosion on sloping land. Reduce herbicide amounts proportionately to the area of soil actually treated.

Soil-active herbicides Persistent, soil-active herbicides can be applied in early fall through early spring, and activated with rain or sprinkler irrigation if dry conditions persist. Apply lower rates on sandy soils having lower clay or organic matter contents, to reduce or avoid possible injury symptoms. Existing vegetation between rows can be controlled with cultivation.

Postemergence herbicides Contact herbicides, or plant growth regulator herbicides such as 2,4-D, can be used to control existing broadleaf weeds. 2,4-D controls many broadleaf weeds, but must be applied when weeds are actively growing. Strawberries must be completely inactive during the “summer” or “winter” dormancy to reduce the chance of crop injury from 2,4-D.

Warning Using 2,4-D or similar materials involves risk, not only to the crop to which it is applied but also to other crops in nearby fields. However, there may be instances where guidance in using 2,4-D will enhance weed control with minimal chance for crop injury. Be careful to clean all 2,4-D from your equipment, otherwise use separate sprayers before applying another product to other horticultural crops. Under no conditions should you use volatile formulations of 2,4-D or similar materials. Purchase only a product that lists strawberries on the label.

Note Herbicides must be applied at the correct rate and time to selectively control weed growth with minimal chance for injury to strawberries. Obtain more consistent results by reading the herbicide label and other information about the proper application and timing of each herbicide. Suggested rates listed in this guide are stated as pounds of active ingredient per acre (lb ai/A) or pounds of acid equivalent per acre (lb ae/A). For band applications over berry rows, reduce the amount of herbicide applied proportionately to the area within the row actually sprayed.

STRAWBERRIES—New Plantings

acetic acid (Weed Pharm)

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)

Row middles only

Rate 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 to row middles only, 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: protoporphyrinogen oxidase (PPO) inhibitor

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 postemergence to actively growing annual or perennial grasses, including annual bluegrass, as listed on label.

Remarks Consider environmental and plant growth conditions that affect leaf uptake; see label for guidelines. Limited observations suggest that April treatments may cause slight cupping and browning of petals or blossoms. Add crop oil concentrate as described on label.

Caution Do not exceed 32 oz/A Select 2EC per season.

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

Chemical family Cyclohexanedione

DCPA (Dacthal Flowable)

Rate 9 lb ai/A (12 pints/A)

Time Apply soon after transplanting, or preplant incorporate.

Remarks Applications west of Cascades usually perform erratically. Inhibits mitosis.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Phthalic acid

flumioxazin (Chateau)

Rate 0.096 lb ai/A (3 oz/A Chateau)

Time Preplant. For preemergence weed control, apply at least 30 days before transplanting and before plastic mulch (if used) is laid. In established plantings in spring or summer, apply to row middles only, using a hooded or shielded sprayer before weeds emerge. Do not let spray drift contact strawberry plant foliage.

Remarks May provide some burnback of existing broadleaf weeds. Adding an adjuvant enhances weed burnback but may lead to crop spotting.

Caution Do not exceed 3 oz/A at this timing. Do not apply after fruit set or when fruit is present.

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

Chemical family N-phenylphthalimide

glyphosate (several products)

Rate Consult supplemental label

Time Apply at least 3 days before transplanting.

Remarks Do not apply after transplanting. Inhibits production of three amino acids and protein synthesis.

Site of action Group 9: inhibits EPSP synthase

Chemical family None generally accepted.

lactofen (Cobra)

Nonbearing in Oregon only

Rate 0.25 to 0.38 lb ai/A (16 to 24 oz/A)

Time Apply immediately before or after transplanting, or within 48 hours after transplanting, if soil is placed over plants to minimize contact and possible injury.

Remarks Special local needs label OR-010006. Activate with 0.25 to 0.5 inch water within 48 hours. Grasses are not controlled. Preharvest interval is 1 year.

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

Chemical family Diphenylether

napropamide (Devrinol 2EC)

Rate 4 lb ai/A (8 quarts/A Devrinol 2EC)

Time Apply before weeds germinate, or after cultivating to remove growing weeds.

Remarks Requires sprinkler irrigation the same day to wet soil 2 to 4 inches deep. Applications during the growing season may delay or inhibit rooting (pegging) of runners. Some growers apply 2 lb ai/A at planting to minimize root pruning and pegging problems, then an additional 2 lb ai/A in fall. Inhibits root growth.

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

Chemical family Acetamide

pendimethalin (Prowl H2O)

First-year, nonbearing strawberries; Oregon and Washington

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

Time Apply preemergence as a broadcast spray to the soil surface before or within 7 days after transplanting strawberries.

Remarks Most effective if rain or irrigation incorporates herbicide into weed emergence zone within 7 days. Do not apply to strawberry bed if bed is later to be covered with plastic.

Caution 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 0.19 to 0.47 lb ai/A (2 to 2.5 pints Poast/A)

Time Apply at optimum growth stage listed on label.

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 by 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 Do not exceed 2.5 pints/A per season.

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

Chemical family Cyclohexanedione

sulfentrazone (Spartan 4F)

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

Time Apply pre-plant or post-transplant, prior to weed emergence.

Remarks Preemergent applications must be activated by sufficient irrigation (0.5 to 1”) within 7-10 days.

Caution Application to strawberry plants with newly emerged growth is not recommended due to leaf burning and possible stand loss. 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: protoporphyrinogen oxidase (PPO) inhibitor

Chemical family Triazolinone

STRAWBERRIES—Established Plantings—Early Fall or Winter Applications

Cereal Interplant On sloping land, spring cereals such as barley or oats are sown between rows to reduce or slow runoff and possible erosion. The cereals are killed in spring with cultivation or herbicides before excessive growth.

carfentrazone-ethyl (Aim EC)

Rate May be applied 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. See 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: protoporphyrinogen oxidase (PPO) inhibitor

Chemical family Triazolinone

clethodim (Select 2EC and others)

Rate 0.09 to 0.125 lb ai/A (6 to 8 oz/A Select 2EC). Consult label for rate required to control different grasses.

Time Apply to actively growing grasses at recommended 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. Preharvest interval is 4 days.

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

Chemical family Cyclohexanedione

clopyralid (Stinger)

Oregon and Washington only

Rate 0.125 lb ai/A (0.33 pint/A Stinger)

Time Apply after harvest, from September 15 to November 15.

Remarks Special local needs labels OR-030031 and WA-030035. Preharvest interval is 30 days.

Caution Do not exceed a total of 0.25 lb ai/A (0.66 pint/A) per year. Do not use with surfactants or tank mix with other herbicides. May cause minor leaf cupping. Do not compost vegetation treated with Stinger.

Site of action Group 4: synthetic auxin

Chemical family Pyridine

DCPA (Dacthal Flowable)

Rate 6 to 9 lb ai/A (8 to 12 pints/A Dacthal Flowable)

Remarks Applications west of Cascades usually perform erratically. Elsewhere, apply in fall or early spring to control late summer weeds. Do not apply after first bloom. Inhibits mitosis.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Phthalic acid

flumioxazin (Chateau)

Rate 0.096 lb ai/A (3 oz/A Chateau)

Time Apply during winter dormancy for preemergence weed control.

Remarks May provide some burnback of existing broadleaf weeds. Experience indicates 2.2 oz/A is sufficient for preemergence weed control. Crop oil concentrate, at 1% v/v, or nonionic surfactant, at 0.25% v/v, may be added to help control emerged broadleaf weeds. Do not apply after fruit set.

Caution Do not exceed 3 oz/A Chateau at this timing.

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

Chemical family N-phenylphthalimide

napropamide (Devrinol 2EC)

Rate 4 lb ai/A (8 quarts/A Devrinol 2EC)

Time Apply fall through early spring before weeds emerge, preferably in November or December.

Remarks If applied March through October, requires sprinkler irrigation to wet soil 2 to 4 inches deep, to reduce herbicide degradation. Due to possible carryover in wheat rotations, use other weed controls the final year of strawberry production, or plow deeply to dilute soil residue. Inhibits root growth.

Caution Do not exceed 4 lb ai/A per year.

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

Chemical family Acetamide

pendimethalin (Prowl H2O)

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

Time May be applied to strawberries in fall or winter dormancy, but prior to onset of new seasonal growth from crowns.

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. Preharvest interval is 35 days.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Dinitroaniline

sethoxydim (Poast)

Rate 0.38 to 0.48 lb ai/A (2 to 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 stressed from drought, high temperatures, or low fertility. Resistant grasses include annual bluegrass and all fine fescues; quackgrass can be suppressed. Note special precautions on Sinbar applications.

Caution Do not exceed 2.5 pints/A per season. Preharvest interval is 7 days. Inhibits fatty acid production, cell membranes, and new growth.

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 harvest at time of bed renovation where overhead irrigation is available for activation, or apply in October or November and activate with rain. Apply only once per year and do not use on sandy or coarse soils.

Remarks Established weed seedlings will not be controlled.

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 to established plantings during dormancy. Special local needs labels OR-110009 and WA-110007.

Remarks Rainfall or irrigation needed to activate herbicide within 14 days of application. Do not apply within 70 days of harvest.

Caution Application to strawberry plants with new emerged growth is not recommended due to leaf burning and possible stand loss. 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: protoporphyrinogen oxidase (PPO) inhibitor

Chemical family Triazolinone

terbacil (Sinbar)

Rate 0.1 to 0.3 lb ai/A (2 to 6 oz Sinbar/A)

Time Apply during winter dormancy, before weeds are 2 inches tall or wide. Apply split treatments of up to 0.3 lb ai/A during bed renovation and again in winter; do not exceed 0.4 lb ai/A (8 oz/A) per year. Apply to strawberries established at least 6 months.

Caution Do not use on sandy, loamy sands, gravelly soils or soils containing less than 2% organic matter. Avoid use for 2 years if replanting is planned, and consult label for re-cropping information.

Site of action Group 5: photosystem II inhibitor

Chemical family Uracil

STRAWBERRIES—Established Plantings—Weed Control in Late Winter and Spring

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 in late winter when crops are dormant, in 20 to 25 gal/A water. Apply before February to mitigate potential injury to fruit.

Remarks Make sure label includes strawberries; 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 using 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)

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. 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.

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. Can be used up to and including day of harvest.

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: protoporphyrinogen oxidase (PPO) inhibitor

Chemical family Triazolinone

clopyralid (Stinger)

Oregon and Washington only

Rate 0.125 lb ai/A (0.33 pint/A Stinger)

Time Apply in spring, before first bloom.

Remarks Special local needs labels OR-030031 and WA-030035.

Caution Do not exceed a total of 0.25 lb ai/A (0.66 pint/A) per year. Do not use with surfactants or tank mix with other herbicides. May cause minor leaf cupping. Do not compost vegetation treated with Stinger. Preharvest interval is 30 days.

Site of action Group 4: synthetic auxin

Chemical family Pyridine

flumioxazin (Chateau)

Rate 0.096 lb ai/A (3 oz/A Chateau)

Time Apply in early spring before weed emergence and fruit set.

Remarks Apply only to row middles using a hooded or shielded sprayer. May give some burnback of existing broadleaf weeds. Adding an adjuvant enhances weed burnback but may lead to crop spotting. Apply only prior to fruit set.

Caution Do not exceed 3 oz/A per application. Do not apply over the top of strawberries. Do not let spray drift contact fruit or foliage.

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

Chemical family N-phenylphthalimide

pendimethalin (Prowl H2O)

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

Time May be applied to strawberries in winter dormancy prior to onset of new seasonal growth from crowns, or in spring as a band between rows.

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. Preharvest interval is 35 days.

Site of action Group 3: microtubule assembly inhibitor.

Chemical family Dinitroaniline

STRAWBERRIES—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)

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: protoporphyrinogen oxidase (PPO) inhibitor

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-EC)

Rate 4 lb ai/A (8 quarts/A Devrinol 2EC)

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 0.38 to 0.47 lb ai/A (2 to 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 Special local needs labels OR-110009 and WA-110007. 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: protoporphyrinogen oxidase (PPO) inhibitor

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 re-cropping 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