Blueberries, Gooseberries, Currants, and Elderberries
Ed Peachey 
Revised November 20, 2008

BLUEBERRIES, GOOSEBERRIES, CURRANTS, AND ELDERBERRIES—Weed and Vegetation Management
General strategy  Blueberries respond to moist, aerated mulch such as sawdust, where roots proliferate within the crop row, and to good drainage between rows. Other berries are managed as caneberries are.
Mowing or flailing  Frequently mowing improved turf grasses or perennial sods improves water infiltration and drainage in blueberry aisles. Vegetation between rows of other berries is mowed or flailed.
Herbicides  Although blueberries respond to an undisturbed, competition-free strip of one-third to one-half the total area of the field, precision is required because blueberry roots are concentrated near the soil surface. Choose combinations of practices including herbicides that act together to achieve your desired level of vegetation management within berry plantings.
BLUEBERRIES, GOOSEBERRIES, CURRANTS, AND ELDERBERRIES—Site Preparation
•  glyphosate (numerous product names)
Rate  Consult labels
Time  Apply to weeds at least 10 days before planting the crop. 
Remarks  Use highest rate on field bindweed. Inhibits production of three amino acids and protein synthesis.
Caution  Do not apply to weeds stressed by drought, weather, or maturity. Rain within 6 hr after applying may reduce effectiveness.
Site of action  Group 9: inhibits EPSP synthase
Chemical family  None generally accepted
BLUEBERRIES, GOOSEBERRIES, CURRANTS, AND ELDERBERRIES—New Plantings
•  sawdust
Rate  2- to 4-inch layer
Time  Apply immediately after transplanting to suppress annual weed germination and to conserve soil moisture.
Remarks  Controls perennial weeds before planting. Sometimes lower rates of registered herbicides for new plantings can enhance weed control, if applied before spreading the mulch.
•  napropamide (Devrinol 50DF)
blueberries and currants only
Rate  4 lb ai/A (8 lb/A Devrinol)
Time  Apply after transplanting to firm soil before weeds germinate or sawdust is spread.
Remarks  On day of treatment, wet soil 2 to 4 inches deep to reduce degradation by sun and to activate herbicide. Where convenient, shallow mechanical incorporation appears to improve activation (inhibits root growth).
Site of action  Group 15: inhibits very long chain fatty acid synthesis
Chemical family  Acetamide
•  oryzalin (Surflan DF)
Rate  2 to 6 lb ai/A (2.4 to 7.1 lb/A)
Time  Apply after transplanting to firm soil before weeds germinate or sawdust is spread. 
Remarks  Requires sprinkler irrigation, rain, or shallow cultivation (1 to 2 inches) for activation. Avoid exposure of transplant roots contacting treated soil. Inhibits mitosis, primarily in roots.
Caution  Do not apply to lowbush blueberries.
Site of action  Group 3: microtubule assembly inhibitor
Chemical family  Dinitroaniline
•  oxyfluorfen + isoxaben + trifluralin (Showcase) 
nonbearing blueberries only
Rate  100 to 200 lb/A, depending on target weed
Time  Apply during dormant season to blueberries that will not bear fruit for at least 1 yr.
Remarks  Apply evenly with drop or rotary-type spreader to avoid crop injury. Apply to weed-free soil. Controls many weeds that grow from seeds but will not control weeds that emerge from existing stolons, rhizomes, or root pieces. Control existing weeds with cultivation or postemergence herbicides. Activate within 3 days using 0.5 inch of water before weeds begin to emerge. See label for repeat treatments. 
Caution  Do not make repeat applications at 150 lb/A or greater within 60 days of a previous application. Do not apply when wind favors drift of granule from the target area.
Site of action  (oxyfluorfen) Group 14: inhibits protoporphyrinogen oxidase; (isoxaben) Group 21: inhibits cell wall biosynthesis Site B; (trifluralin) Group 3: microtubule assembly inhibitor
Chemical family  (oxyfluorfen) diphenylether; (isoxaben) benzamide; (trifluralin) dinitroaniline
•  isoxaben + trifluralin (Snapshot) 
nonbearing currants and gooseberries
Rate  100 to 200 lb/A, depending on target weed
Time  Apply during dormant season to crops that will not bear fruit for at least 1 yr.
Remarks  Apply evenly with drop or rotary-type spreader to avoid crop injury. Apply to weed-free soil. Controls many weeds that grow from seeds but will not control weeds that emerge from existing stolons, rhizomes, or root pieces. Control existing weeds with cultivation or postemergence herbicides. Activate within 3 days using 0.5 inch of water before weeds begin to emerge. See label for repeat treatments. 
Caution  Do not make repeat applications at 150 lb/A or greater within 60 days of a previous application. Do not apply when wind favors drift of granule from the target area.
Site of action  (isoxaben) Group 21: inhibits cell wall biosynthesis Site B; (trifluralin) Group 3: microtubule assembly inhibitor
Chemical family  (isoxaben) benzamide; (trifluralin) dinitroaniline
•  fluazifop (Fusilade DX)
nonbearing blueberries, currants, and gooseberries only
Rate  0.25 to 0.38 lb ai/A (16 to 24 oz/A) 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 yr. Grazing is prohibited.
Site of action  Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family  Aryloxyphenoxy propionate
•  norflurazon (Solicam)
blueberries only
Rate  1.97 to 3.93 lb ai/A (2.5 to 5 lb/A) depending on soil type
Time  West of Cascades, immediately after planting. East of Cascades, wait 6 mo after planting before applying.
Remarks  Soil surface must be weed free and relatively free of plant residues or debris. Inhibits yellow pigment formation, bleaching green chlorophyll.
Caution  Do not use on nursery stock. 
Site of action  Group 12: bleaching; inhibits carotenoid synthesis
Chemical family  Pyridazinone
•  sethoxydim (Poast)
blueberries only
Rate  0.19 to 0.47 lb ai/A (1 to 2.5 pints/A) depending on target weed species
Time  Identify susceptible grasses and apply at optimum growth stage listed on the label.
Remarks  Add 2 pints/A of a nonphytotoxic crop oil concentrate to improve leaf absorption. Control often is erratic if grasses are 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 5 pints/A per season. Preharvest interval is 30 days. 
Site of action  Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family  Cyclohexanedione
•  clethodim (Select, Envoy, and others)
nonbearing blueberries, currants, and gooseberries
Rate  0.063 to 0.125 lb ai/A (4 to 8 fl oz/A Select) depending on target weed species
Time  Apply to actively growing grass weeds, including annual bluegrass, at labeled growth stage. 
Remarks  Read label carefully for adjuvant instructions and for information about effects of rain within 1 hr, applications of other pesticides, or cultivation.
Caution  Do not broadcast spray. Direct spray at base of the plant where grassy weeds are growing. Do not exceed 68 fl oz/A per season. Do not apply to nonbearing crops grown for rootstock.
Site of action  Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family  Cyclohexanedione
•  glyphosate (numerous product names)
Rate  Consult label
Time  Apply to actively growing weeds either as site preparation or in nonbearing crops 1 yr before first harvest.
Remarks  Avoid contact with green foliage or suckers of crop. 
Caution  Do not exceed 12.8 pints/A product per year. Follow all precautions on label.
Site of action  Group 9: inhibits EPSP synthase
Chemical family  None generally accepted
•  simazine (Princep)
blueberries only
Rate  2 lb ai/A (2 quarts/A)
Time  Apply in spring within 2 wk after transplanting to firm soil before weeds are established.
Remarks  Use lowest rate possible. Mix with low rates of other herbicides that have other types of action. 
Caution  Do not use on light-texture soils. Requires surface moisture to activate. Do not apply if berries are present. 
Site of action  Group 5: photosystem II inhibitor
Chemical family  Triazine
BLUEBERRIES, GOOSEBERRIES, CURRANTS, AND ELDERBERRIES—Established Plantings—Winter or Dormant Applications that Persist in Soil
•  flumioxazin (Chateau)
highbush blueberries only
Rate  0.19 to 0.38 lb ai/A (6 to12  oz/A Chateau WDG 51%)
Time  Preferred timing is fall, to maximize potential of rain to activate the herbicide.
Remarks  West of Cascade mountains in Oregon and Washington in specified counties. 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 per application or 24 oz/A in 1 yr. Use the 6 oz/A rate if soil has significant sand or gravel.
Caution  Do not apply from budbreak through harvest. Do not apply to blueberries established less than 2 yr. Avoid direct or indirect spray contact with foliage or green bark. Do not apply to soils that are susceptible to dispersal by wind. This herbicide can move to susceptible crops on soil particles and cause damage. Do not apply within 300 yd of nondormant pears. Do not mow treated areas between budbreak and final harvest. Dust created by mowing may injure susceptible plants.
Site of action  Group 14: protoporphyrinogen oxidase inhibitor
Chemical family  N-phenylphthalimide
•  diuron (Direx 4L and several other products)
blueberries ,gooseberries, and lingonberries
Rate  1.6 to 2.4 lb ai/A (3.2 to 4.8 pints/A)
Time  Apply in winter as single application, or apply 3.2 lb ai/A in October and again in March.
Remarks  Reduce rate or rotate to other herbicides after achieving weed control. Sprinkler irrigate if applied before fall rains begin. Spray soil around base of plant, avoiding crop foliage.
Caution  Do not use within 1 yr after planting or on plants being tip layered. Do not apply on very sandy or gravelly soils. Can be rotated with simazine or other herbicides to reduce weed shifts.
Site of action  Group 7: photosystem II inhibitor
Chemical family  Substituted urea
•  simazine (Princep)
blueberries only
Rate  Consult labels
Time  Apply in winter as single application, or split application with 2 quarts/A in spring and 2 quarts/A in the fall.
Remarks  Reduce rate or rotate with other herbicides after achieving weed control. Requires surface moisture to activate. Can be rotated with diuron or other herbicides (except terbacil) to reduce weed shifts. Inhibits photosynthesis.
Caution  Do not use on light-textured soils. Requires surface moisture to activate. Do not apply when berries are present.
Site  of action  Group 5: photosystem II inhibitor
Chemical family  Triazine
•  terbacil (Sinbar)
blueberries only
Rate  1.6 to 2.4 lb ai/A (2 to 3 lb/A Sinbar) depending on soil texture and organic matter content
Time  Apply in fall after harvest or in spring to blueberries established at least 1 yr and to seedling or emerging weeds.
Remarks  Some growers have reported injury. Use product on small areas until you are satisfied with the results. Sprinkler irrigate if rain does not fall within 2 wk. Reduce rates by as much as half, or rotate with other herbicides after achieving effective weed control. Calibrate sprayer and apply with tractor-mounted, fixed-boom sprayer using a constant speed and rate of delivery. (Inhibits photosynthesis.)
Caution  Do not apply on gravelly soils, soils with less than 1% organic matter, or on weak plants or eroded areas with exposed roots. Avoid use for 2 yr if replanting is anticipated. Can rotate with diuron or other herbicides (except simazine) to reduce weed shifts. 
Site of action  Group 5: photosystem II inhibitor
Chemical family  Uracil
•  hexazinone (Velpar DF)
blueberries only
Rate  1 to 3 lb ai/A (4 to 12 pints/A) depending on blueberry type and soil type
Time  Plants should be established for 3 yr. Apply to pruned blueberry plants before leaves emerge in spring.
Remarks  This herbicide can injure other crops in western Oregon. Consult label for all precautions including blueberries established at least 3 yr or more. 
Site of action  Group 5: photosystem II inhibitor
Chemical family  Triazinone
•  norflurazon (Solicam)
blueberries only
Rate  1.97 to 3.93 lb ai/A (2.5 to 5 lb/A) depending on soil type
Time  Apply as a directed spray from fall to early winter before weeds emerge.
Remarks  Soil surface must be weed-free and relatively free of plant residues or debris. Multiple or sequential applications can be made, but total amount applied in any 12 mo must not exceed the maximum rate listed on the label for that crop and soil texture. Inhibits yellow pigment formation, bleaching green chlorophyll.
Caution  Do not use on nursery stock. 
Site of action  Group 12: bleaching; inhibits carotenoid synthesis
Chemical family  Pyridazinone
•  dichlobenil (Casoron)
blueberries only
Rate  4 to 6 lb ai/A (100 to 150 lb/A granular product)
Time  Apply midwinter immediately before a cold rain to reduce volatility and enhance weed suppression.
Remarks  Weigh and distribute exact quantities over precisely measured areas. Adjust rates on light, sandy soils and treat at least 4 wk after planting or preferably the next winter. Precision application of the higher rate over 3 consecutive years suggests adequate crop tolerance under the following conditions. Oregon results over 9 yr suggest perennial weeds can be suppressed with 4-, 3-, and 2-lb ai/A rates applied in 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
•  dichlobenil (Casoron CS)
blueberries only
Rate  1.96 to 3.92 lb ai/A (1.4 to 2.8 gal/A)
Time  Apply midwinter immediately before a cold rain to reduce volatility and enhance weed suppression.
Remarks  Liquid formulation of encapsulated crystals of dichlobenil. Controls most germinating seeds and seedlings of annual and perennial grasses, and broadleaf weeds. Do not use on light sandy soils. Do not apply with high or gusty wind, high temperatures, low humidity, or temperature inversions. Inhibits cellulose and cell wall formation.
Caution  Use only around well-established plants; typically wait until 1 yr after transplanting. Grazing livestock is prohibited. 
Site of action  Group 20: inhibits cell wall synthesis Site A
Chemical family  Nitrile
•  napropamide (Devrinol)
blueberries and currants only
Rate  4 lb ai/A (8 lb/A)
Time  Apply fall through spring before weeds germinate, or apply 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 wk after application. Irrigate within 24 hr to wet soil 2 to 4 inches deep when applied March through October. Excessive plant residues on soil surface reduce performance (inhibits root growth).
Site of action  Group 15: inhibits very long chain fatty acid synthesis
Chemical family  Acetamide
•  oryzalin (Surflan DF)
Rate  2 to 6 lb ai/A (2.4 to 7.1 lb/A)
Time  Apply late fall or early spring to bare soil or after existing vegetation has been destroyed by tillage or by a foliar-active herbicide.
Remarks  Use higher rates, or apply split treatments in fall and spring for longer residual control. Irrigate with at least 0.5 inch of water or rain to activate herbicide. Shallow cultivation can control newly germinated weeds without reducing herbicide activity. Allow 24 mo before planting vegetables after berries. Inhibits mitosis, primarily in roots.
Caution  Do not apply to lowbush blueberries.
Site of action  Group 3: microtubule assembly inhibitor
Chemical family  Dinitroaniline
•  pronamide (Kerb)
blueberries only; Oregon and Washington only
Rate  1 to 2 lb ai/A (2 to 4 lb/A) depending on target weed species
Time  Apply once in fall or winter, preferably October to December when ground is not frozen.
Remarks  Use lower rates on annual grasses, higher rates on perennial grasses such as quackgrass. Requires moisture from rain or irrigation to activate. Use only in berries established at least 3 mo. Degraded by microorganisms at higher temperatures. Inhibits root growth.
Caution  A restricted-use pesticide.
Site of action  Group 3: microtubule assembly inhibitor
Chemical family  Benzamide
BLUEBERRIES, GOOSEBERRIES, CURRANTS, AND ELDERBERRIES—Established Plantings—Directed Applications in or between Berry Rows
•  carfentrazone (Aim)
shielded spray between rows
Rate  0.016 to 0.031 lb ai/A (1 to 2 fl oz/A in at least 10 gal/A of 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.
Caution  Must prevent spray from contacting green stem tissue, foliage, blooms, or fruit. Hooded sprayers must totally enclose the spray pattern.
Site of action  Group 14: inhibits protoporphyrinogen oxidase
Chemical family  Triazinone
•  mesotrione (Callisto)
highbush blueberries and lingonberry
Rate  0.094 to 0.188 ai/A (3 to 6 fl oz/A)
Time  Prebloom, post-directed spray.
Remarks  Supplemental label. May be applied as a split application, but no more than 6 oz/A per year. Use crop oil concentrate at 1% v/v to enhance weed control. Separate applications by 14 days. Has both burndown and soil-residual activity. Controls many broadleaf weeds but controls few grasses and no perennial weeds.
Caution  Applying after the onset of bloom may result in illegal residues.
Site of action  Group 28: inhibits 4-hydroxyphenylpyruvatedioxygenase (4-HPPD)
Chemical family  Triketone
•  glufosinate (Rely)
Rate  0.75 to 1.5 lb ai/A (3 to 6 quarts/A) 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 may occur. Do not exceed 12 quarts/A of Rely (3 lb ai/A) to berry bushes in a 12-mo period. Preharvest interval is 14 days.
Site of action  Group 10: inhibits glutamine synthase
Chemical family  Phosphinic acid
•  glyphosate (numerous product names)
Rate  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.
Caution  Do not allow drift or mist to contact green foliage or bark, suckers, or vines and renewals less than 3 yr old. When repeat applications are necessary, do not exceed 10.6 lb ai/A in 1 yr. Repeated glyphosate applications have created resistant biotypes of ryegrass in Australian 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.)
Site of action  Group 9: inhibits EPSP synthase
Chemical family  None generally accepted
•  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. Avoid contact with desirable foliage. Directed sprays or hooded sprayers are recommended to protect desirable foliage. 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.
•  lemon grass 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 sites. Foliage contacted by Green Match will be damaged. Directed sprays or hooded sprayers are recommended to protect desirable foliage.  Coverage is very important. Leaf damage is visible within hours. Cool weather may slow activity. No reentry interval. Fast wilting or necrosis of the leaves due to removal of waxy cuticle.
•  sethoxydim (Poast)
blueberries and lingonberries only
Rate  0.19 to 0.47 lb ai/A (1 to 2.5 pints/A) 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.
Caution  Preharvest interval is 30 days for blueberries and 45 days for lingonberries. Do not exceed 5 pints/A per season.
Site of action  Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family  Cyclohexanedione
•  2,4-D (Saber)
highbush blueberries only
Rate  1.4 lb ae/A (3 pints/A Saber)
Time  Apply labeled rate in 50 gal/A water, as a directed spray to the weed or grass strip between rows. Avoid contact with blueberry foliage.
Remarks  Special local needs labels OR-050016 and WA-010009. Apply in spring and fall, depending on broadleaf weeds present.
Caution  Preharvest interval is 30 days. Do not apply if temperature is expected to exceed 65ºF. Avoid drift within the field and to adjacent crops.
Site of action  Group 4: synthetic auxin
Chemical family  Phenoxy acetic acid
breakhere