Established Plantings-Applications that Persist in the Soil

dichlobenil (Casoron)

Rate 4 to 6 lb ai/A (100 to 150 lb/A Casoron)

Time Apply midwinter, immediately before a cold rain to reduce volatility and improve weed suppression.

Remarks Weigh and distribute over precisely measured area to ensure accurate application. Do not apply until 4 weeks after transplanting. Oregon results over 9 years suggest perennial weeds can be suppressed with 4-, 3-, and 2-lb ai/A rates applied during 3 consecutive years. Inhibits cellulose and cell wall formation.

Caution Grazing livestock is prohibited.

Site of action Group 20: inhibits cell wall synthesis Site A

Chemical family Nitrile

diuron (Karmex DF and others)

Rate 1.6 to 3.2 lb ai/A (2 to 4 lb/A) depending on crop and time of application.

Time Apply higher rate in late fall, or split applications in spring and fall to bare soil, depending on soil type.

Remarks Add a foliar-active herbicide to control existing vegetation. Consult label for information on rates and soil types. Reduce rates after effective weed control is achieved. Can be rotated with simazine or other herbicides to reduce weed shifts. Inhibits photosynthesis.

Caution Do not apply to sandy or gravelly soils, or to full-dwarf rootstocks. Use only on trees established at least 1 year (3 years for peaches). Do not apply if nuts are on the ground.

Site of action Group 7: photosystem II inhibitor

Chemical family Substituted urea

flazasulfuron (Mission)

Rate 0.033 to 0.045 lb ai/A (2.14 to 2.85 oz/A)

Time Pre- and postemergent to broadleaf and grass weeds up to 4 inches tall, and before grasses tiller.

Apply as a directed spray to the soil beneath the trees to prevent injury to the foliage and bark. Must be activated with rainfall or irrigation of 0.25 to 0.5 inch for preemergence control; preemergence efficacy will be best if applied to bare soil. Do not disturb the soil after activation. Use an adjuvant for postemergent applications. Apply only to trees 3 years old or older. Protective sleeves are required for third year trees. If weeds are present, tank mix glyphosate or glufosinate to improve burndown and broaden weed control spectrum. Controls many grasses and broadleaf weeds, including annual ryegrass, roughstalk bluegrass, common mallow, clover, and willowherb. Reentry interval is 12 hours.

Caution Do not apply more than two applications at 2.85 oz/A per year. Preharvest interval is 130 days. Minimum retreatment interval (RTI) is 3 months. Do not apply to stony soils. A 25-foot buffer must be maintained between the point of direct application and the closest downwind edge of sensitive terrestrial habitats (forested areas, riparian areas), freshwater habitats (lakes, rivers, sloughs), and estuarine/marine habitats.

Site of action Group 2

Chemical family Sulfonylurea

flumioxazin (Chateau SW)

Rate 0.19 to 0.38 lb ai/A (6 to 12 oz/A Chateau SW). Refer to organic matter, soil types, and rates listed on label to control for various broadleaf weeds.

Time Stone fruit and pear: Between final harvest and budbreak and before weeds emerge. Apple: between final harvest and pink bud. Preferred timing is in fall when rain will activate the herbicide.

Remarks Trees must be established 1 year unless protected from spray with nonporous wraps, grow tubes or waxed containers. Do not allow spray to contact green or immature bark of shoots. Apply to a weed-free surface. Chateau has limited postemergence activity that is enhanced by adding surfactants. Add 0.25% v/v nonionic surfactant or 1% crop oil concentrate to enhance postemergence burndown activity. Tank-mix with herbicides such as glyphosate, glufosinate, or paraquat to kill large weeds. Residual weed control will be reduced if vegetation prevents the spray from reaching the soil. Moisture is necessary to activate the herbicide for residual weed control. Dry weather after application may reduce effectiveness. Do not exceed 12 oz/A product per application or 24 oz/A per year. Use the 6 oz/A rate if soil has significant sand or gravel.

Caution Preharvest interval is 60 days. Do not apply to soils that are susceptible to dispersal by wind. This herbicide can move to susceptible crops on soil particles causing damage. Do not apply within 300 yards of nondormant pears. Do not mow treated areas between budbreak and final harvest. Dust created by mowing may injure susceptible plants. Avoid direct or indirect spray contact with foliage or green bark. Do not apply to trees established less than 1 year.

Site of action Group 14: protoporphyrinogen oxidase inhibitor

Chemical family Diphenylether

indaziflam (Alion)

Rate 0.046 to 0.085 lb ai/A (3.5 to 6.5 oz/A product), depending on soil texture.

Time Apply in fall to early spring to firmed soil that does not have cracks.

Remarks Apply to stone and pome fruit trees that have been established 3 years and to nut trees that have been established 1 year. Existing vegetation must be controlled with glyphosate or burndown herbicides such as glufosinate or paraquat. Controls annual broadleaf and grass weeds and perennial weeds from seed only. Existing perennial/biennial weeds growing from roots will not be controlled. Rainfall or irrigation of 0.25 inch or more within 3 weeks of application is required for maximum efficacy. Preharvest interval is 14 days.

Caution Avoid direct contact with foliage, green bark, or roots of desired species. Clean spray tanks thoroughly after use. Make sure soil is settled around trees and there are no cracks in the soil. Surface and groundwater advisories are included on the label because of potential to harm nontarget aquatic organisms and potential for runoff and percolation to ground water. A well-maintained and level vegetated buffer strip of 25 ft or more will help reduce runoff. Application of indaziflam 48 hours or more before rain is forecasted will reduce runoff potential.

Site of action Group 29: inhibits cellulose biosynthesis

isoxaben (Trellis, Gallery)

Bearing nuts; nonbearing pome and stone fruits

Rate 0.495 to 0.998 lb ai/A (0.66 to 1.33 lb/A product)

Time Apply late summer to early fall, in early spring, or immediately after cultivation to debris-free soil surface. Activate with 0.5 inch water or shallow cultivation before weeds begin to emerge.

Remarks Identify weeds and adjust rates according to charts listed on label. Chemical stability remains adequate when left on soil surface for 21 days. Preharvest interval in nuts is 60 days. Gallery limited to nonbearing sites.

Caution Do not apply to newly transplanted crops until the soil has settled and cracks disappear.

Site of action Group 21: inhibits cell wall synthesis Site B

Chemical family Benzamide

napropamide (Devrinol)

Hazelnuts only

Rate 4 lb ai/A (8 lb/A DF and XT formulations)

Time Apply fall through spring before weeds germinate, or mix with foliar-active herbicide to control existing vegetation.

Remarks Irrigation or shallow incorporation is recommended for treatments made November through February if no rain falls within 2 weeks after treatment. Irrigate within 24 hours to wet the soil 2 to 4 inches deep when applied March through October. Results are best if herbicide is mechanically incorporated into the soil immediately after application. Performance is reduced when excessive plant residues are on soil surface. Inhibits root growth.

Caution Do not apply to frozen soil. Do not graze livestock in treated area.

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

Chemical family Acetamide

norflurazon (Solicam)

Rate 1.95 to 3.9 lb ai/A (2.5 to 5 lb/A Solicam)

Time Apply in fall to early spring, before weeds emerge, to soil relatively free of plant residues.

Remarks Activation requires ample irrigation or rain within 2 to 4 weeks. See label for rates and soil types. Orchards must be established at least 18 months except for newly planted apples, which can be treated after soil settles around tree roots. In cherries, use lower rates and rotate with other soil-applied herbicides to reduce chances of phytotoxic carryover. Avoid contact with fruit and crop foliage. Inhibits yellow pigment formation, causing bleaching of green chlorophyll.

Caution Do not graze livestock in treated area.

Site of action Group 12: bleaching; inhibits carotenoid biosynthesis

Chemical family Pyridazinone

oryzalin (Surflan AS)

Rate 2 to 6 lb ai/A (2 to 6 quarts/A Surflan)

Time Apply late fall or early spring to bare soil, or after tillage or a foliar-active herbicide has destroyed existing vegetation.

Remarks Use higher rates for longer residual control. Irrigate with 0.5 inch of water or rain to activate herbicide. Shallow cultivation can control newly germinated weeds without reducing herbicide activity. Inhibits mitosis, primarily in roots.

Caution Grazing is prohibited.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Dinitroaniline

oxyfluorfen (Goal 2XL)

Rate 1.25 to 2 lb ai/A (5 to 8 pints/A Goal 2XL)

Time Apply only beneath healthy trees. Direct spray toward tree base, avoiding direct plant contact. Acts as a contact herbicide, either directly on broadleaf weeds or at soil the surface as weeds emerge.

Remarks Controls broadleaf weeds pre- and postemergence depending on application rate and weed species.

Site of action Group 14: inhibits protoporphyrinogen oxidase

Chemical family Diphenylether

oxyfluorfen + penoxsulam (Pindar GT)

Rate 1.47 lb ai/A oxyfluorfen + 0.015 lb ai/A penoxsulam (1.5 to 3 pints/A)

Time Dormant application only, after harvest up to bud swell as an early fall to late winter/early spring application

Remarks Trees must be established 4 years. Apply prior to germination of weeds or as an early postemergence when weeds are small and actively growing. Must be activated with rainfall or irrigation for effective preemergence control. Add adjuvants for postemergence applications. Any cultural practices that disturb or redistribute surface soil following treatment will reduce weed control effectiveness. PHI is 60 days

Caution Do not apply more than 3 lb ai oxyfluorfen per acre per year from any combination of applications of Pindar GT, GoalTender, Goal 2XL or any product containing oxyfluorfen. Do not apply to trees grown in soil that contains less than 20% clay and/or greater than 70% sand.

Site of action (oxyfluorfen) Group 14: inhibits protoporphyrinogen oxidase; (penoxsulam) Group 2: acetolactate synthase (ALS) inhibitor

Chemical family (oxyfluorfen) Diphenylether; (penoxsulam) Triazolopyrimidine

pendimethalin (Prowl)

Rate Prowl H2O: 1.9 to 6 lb ai/A (2 to 6.34 quarts/A), depending on crop and desired length of weed control. Prowl 3.3 EC: 1.98 to 3.96 lb ai/A (2.4 to 4.8 quarts/A)

Time Apply before weed emergence.

Remarks May be surface applied preemergence or surface incorporated. Prowl is most effective if incorporated into soil with rain, irrigation, or shallow mechanical incorporation. Apply in single application or sequentially with an interval of 30 days or more. Do not exceed 4 quarts/A per year. Do not feed forage or graze livestock in treated orchards. Preharvest interval is 60 days.

Caution Do not apply over tops of trees with leaves, bud, or fruit. Apply directly to ground beneath the trees or areas between rows.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Dinitroaniline

pronamide (Kerb)

Rate 1 to 4 lb ai/A (2 to 8 lb/A Kerb 50W)

Time Apply once a year, in fall after harvest, but before leaves drop and soil freezes.

Remarks Apply to soil relatively free of plant residues. Requires moisture from rain, snowmelt, or irrigation to activate. Use lower rates for annual grasses and susceptible broadleaf weeds; higher rates for perennials such as quackgrass. Use only on orchards established at least 6 mo. Inhibits root growth.

Caution A restricted-use herbicide. Do not graze livestock in treated area.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Benzamide

saflufenacil (Treevix 70% WDG)

Apple, pear, and walnuts only

Rate 0.044 lb ai/A (1oz/A)

Time Directed postemergence.

Remarks Controls annual broadleaf weeds and suppresses growth of some perennials. Does not control grasses. Adjuvants are needed to maximize burndown control. Up to 3 applications allowed each year (3 oz/A). Preharvest interval of 7 days on nuts. Trees must be established for 12 months. Protect bark of young (2-3 year old) trees. Consult label for accepted crop use.

Caution Contact with foliage will cause damage. Causes substantial but temporary eye damage; PPE includes protective eyeware.

Site of action Group 14: Protoporphyrinogen inhibitor

Chemical family Benzamide

simazine (Princep Caliber 90 and 4L)

Rate 2 to 4 lb ai/A (2 to 4 quarts/A Princep 4L; 2.2 to 4.4 lb/A Caliber 90)

Remarks Oregon special local needs label (OR-080038) on sweet cherries for Princep Caliber 90 for use where soils have some buffering capacity by partially adsorbing the herbicide. Tart cherries have a Section 3 label for Princep 4L in Oregon and Washington.

Caution Do not apply on light, sandy, or rocky soils with little organic matter. Trees must be established 2 years or more. Note comments above. Apply 150 days before apple harvest.

Site of action Group 5: photosystem II inhibitor

Chemical family Triazine

sulfentrazone (Zeus XC)

Rate 0.25 to 0.375 lb ai/A (8 to 12 oz/A)

Time Apply as a dormant application in the fall or spring.

Remarks Controls broadleaf weeds, some grasses, and nutsedge. Zeus XC should be applied as a uniform broadcast soil application to orchard floors and furrows or as a uniform band directed at the base of trees. Precipitation of at least 0.5 inches is required for activation and residual control. For enhanced burndown of emerged weeds, carfentrazone, glufosinate, and glyphosate can be added. May be tank mixed with other labeled herbicides to broaden weed spectrum. Apply to trees that have been established for a minimum of 3 years.

Caution Do not apply to frozen soils. Do not apply more than 0.375 lb of sulfentrazone per 12-month period. The 12-month period begins with the initial application. Avoid direct and indirect contact with green foliage or bark. Wrap in nonporous wrap to keep spray solution off of green tissue. Preharvest interval is 3 days.

Site of action Group 14: protoporphyrinogen oxidase inhibitor

Chemical family Triazinone

terbacil (Sinbar 80)

Apples and peaches, all other uses are for nonbearing fruit trees

Rate 0.4 to 0.8 lb ai/A (0.5 to 1 lb/A), newly established; 2 to 4 lb/A Sinbar, depending on soil type.

Time Apply spring or fall before weeds germinate or when they are in early seedling stage.

Remarks Consult label for rates, soil types, and organic matter contents. Reduce rates after weeds are controlled. Avoid use for 2 years if replanting is anticipated. Grazing is prohibited.

Caution Do not apply to sandy or gravelly soils or to soils with less than 1% organic matter. Use only on orchards established at least 3 years. Should be rotated with other herbicides (except simazine) to reduce weed shifts. Do not contact crop foliage or fruit with herbicide spray. Has greater water solubility than diuron or simazine. Preharvest interval is 60 days. One application per year in Columbia Basin, Washington.

Site of action Group 5: photosystem II inhibitor

Chemical family Uracil

trifluralin (Treflan 4L)

Rate 0.5 to 1 lb ai/A (1 to 2 pints/A Treflan 4EC)

Time Apply preemergence for annual and broadleaf weed control, and incorporate with tillage that will not injure the crop.

Remarks Consult label for calibration and application instructions. Use to supplement other weed control practices.

Caution Apply only when wind speed and direction minimize drift to nontarget areas. Avoid contacting fruit and foliage with treated irrigation water. Prevent groundwater contamination by following all requirements of the irrigation system.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Dinitroaniline