Crop Profile for Strawberries in Oregon

Production Regions (8, 9):
Almost all of Oregon's strawberries are grown west of the Cascade Mountains in the Willamette Valley. Fertile soils, mild winters and cool summers allow growers to produce high quality berries with good flavor, color and texture. Marion County has the most strawberry acreage in the state (47%), followed by Washington County (22%). Other Willamette Valley counties producing strawberries include Benton, Clackamas, Columbia, Lane, Linn, Multnomah, Polk, and Yamhill. There is also some small acreage in the north central and southwestern parts of the state.

Cultural Practices

Oregon strawberries are grown as a perennial, with fields remaining productive for two to four years. Many fields are productive for only two seasons due to declining plant vigor, which is commonly a result of root rot disease or root weevil larvae feeding. Plants do not produce a marketable crop in the planting year, but will bear fruit in subsequent years. Harvest generally begins in early June and lasts for about three weeks. The fruit is harvested by hand, with the cap (calyx and stem) being removed from the berry if the berries are destined for processing. A very small amount of acreage is devoted to producing day-neutral strawberries, which bear fruit continuously from June until early fall, and are sold for fresh market.

Perennial weeds are controlled prior to planting with a non-selective herbicide, such as glyphosate, in the fall or early spring. Soil fumigation for weed and disease control is sometimes used but is not common due to the high costs associated with this practice. In preparation for planting, the soil is disked and cultivated to produce a smooth surface. Some growers create and plant on raised beds, which can help reduce incidence of root rot and fruit rot diseases; however, raised beds are more difficult to maintain and are not common.

Strawberry crowns are planted in the spring. A preemergence herbicide is applied either pre-plant or post-transplant. Irrigation is necessary after planting and weekly, thereafter until rainfall begins in early fall. During the establishment year, plants are fertilized at planting and then again in mid-summer. A preemergence herbicide is again applied in the fall.

In established strawberry fields, it takes approximately 30 to 40 days for the plant to progress from bloom to harvest (7). Fruit rot caused by Botrytis cinerea is common and fungicides are applied during bloom period. Two to four weeks after the last fruits are harvested, the strawberry field is renovated. Renovation involves mowing the plants to just above the crown, disking between the rows, fertilizing and irrigating; a preemergence herbicide is often applied after renovation.

The predominant processing cultivar is Totem, which is firm, sweet and has good internal red color. Other processing cultivars include Hood, Benton, Redcrest, and Puget Reliance.

Insect Pests

Aphids
Shallot aphid (Myzus ascalonicus)
Strawberry aphid (Chaetosiphon fragaefolii)

Pest description: The Shallot aphid is pale greenish-brown and appears in the early spring. The Strawberry aphid is pale green and wingless with small, clubbed hairs on the dorsal surface. Winged adults appear in May and persist into November, with peak population about mid-June. In some years, there is another peak in September and October. They overwinter on plants.

Crop damage: Leaves appear crinkled, curled and, sometimes, yellow due to the virus that is transmitted by the aphid. Damage may spread from small, circular patches to the entire planting.

Chemical control:
Apply chemical treatments when aphids first appear and repeat every two to four weeks, if necessary.

Biological control:

Cultural control: Rogue out plants exhibiting virus symptoms. Isolate new fields from infested fields.

Cyclamen Mite
Steneotarsonemus pallidus

Pest description: The mature mite is flat, lens-shaped, and transparent. The female's hind legs are threadlike. Magnification is needed to see this mite.

Crop damage: Cyclamen mites are found on young, folded leaves along the midvein in early spring. They stunt plants and reduce fruit production. Small bumps felt on leaf midvein and petiole can be indicative of mite feeding. Symptoms are similar to virus symptoms (curled, crinkled leaves). 'Totem' strawberries are very susceptible to cyclamen mite damage.

Chemical Control:

Garden symphylan
Scutigerella immaculata

Pest description: Tiny, centipede-like animals 0.125 to 0.25 inch long. Newly hatched nymphs have six pairs of legs, but at each molt, an additional set of legs is added; adult symphylans have 12 pairs of legs.

Crop Damage: Feeding on roots and root hairs causes stunted plants and reduced yields. Symphylans are exceptionally injurious to young plants.

Chemical control:

Leafrollers
Strawberry leafroller (Ancylis comptana)
Western strawberry leafroller (Compsolechia fragariella)

Pest description: Larvae are brown to greenish and move quickly when disturbed. They overwinter on strawberry plants; moths appear in May. There are several generations a year.

Crop damage: Larvae feed on foliage, which they roll or web together. Leafrollers are seldom a pest that need to be controlled.

Lygus Bugs
Several species, including: Tarnished plant bug (Lygus lineolaris)

Pest description: Adults are 0.25 to 0.5 inches long, winged, and marked with a 'V' on the back. They range in color from light green to shades of grey and brown. Nymphs are smaller and wingless.

Crop damage: Feeding on buds, bloom and immature fruits results in deformed fruits. Lygus bugs are generally not a problem requiring control unless they appear early in the season.

Chemical control:

Meadow spittlebug
Philaenus spumarius

Pest description: Overwinters in the egg stage, which is attached to leaf stems and leaves. Tiny yellow nymphs hatch in April and secrete a white froth over their feeding place on new growth.

Crop damage: Nymphs suck juices from leaves and fruit spurs, causing them to become distorted and stunted. Injury results in reduced yield and inferior fruit quality.

Chemical control: (Treatment before nymphs are half grown are most effective.)

Omnivorous leaftier
Strawberry fruitworm (Cnephasia longana)

Pest description: Adults are tan with brown spots on forewings. At rest, the moths appear bell-shaped. The tiny, orange, first-stage larvae overwinter in crevices of rough-bark trees. Larvae spread by wind into strawberry fields in April and May. Mature larvae are 0.5 to 0.75 inches long with a tan head and creamy-white body.

Crop damage: Larvae feed on folded leaves before they open and on ripening fruit. Larvae tunnel throughout the fruit, rendering it unmarketable.

Chemical control:

Root Weevils
Black vine weevil (Otiorhynchus sulcatus)
Strawberry root weevil (O. ovatus)
Rough strawberry root weevil (O. rugosostriatus)

Pest description: Adults are beetles and are generally black in color; individual beetles may appear light brown to chocolate-brown. They range in size from 0.25 to 0.5 inches long. The black vine weevil is the largest and has small yellow patches on its back. Larvae (grubs) overwinter 2 to 8 inches deep in the soil. They are white with tan heads, legless and have a characteristic c shape.

Crop damage: Adults appear after bloom, begining in May and continuing through July. They feed on leaves prior to egg-laying, leaving characteristic notch marks on leaf margins, although this damage is usually insignificant to plant vitality. The larvae feed on small roots and later on the cambium of large roots and crowns, reducing plant vigor and yield, and causing plant death if larvae are
numerous.

Cultural control:

Biological control (larvae):

Chemical control (adults):

Slugs
Limax spp., Arion spp., Deroceras spp.

Pest description: Slugs are are closely related to snails but have no external shell. Color ranges from grey to brown to black; mature slugs are about 0.5 to 0.75 inches in length.

Crop damage: Slugs make deep, even holes in ripening berries. Heaviest feeding is during cloudy days and at night. Damage is accompanied by slime trails, which can also render fruit unmarketable.

Chemical control:

Strawberry Crown Moth
Synanthedon bibionipennis

Pest description: Adults are clear winged moths which fly in June and July, laying eggs on the undersides of leaves near the crown of the strawberry plant. Larvae are white with a brown head and approximately one inch long. Larvae overwinter in strawberry crowns and roots.

Crop damage: Larvae feed on the inside and outside of strawberry crowns and cause plant stunting and subsequent yield reduction. Severe feeding can cause plant death.

Chemical control:
Because none of the insecticides labeled for use on strawberries displays systemic activity in the plants' crowns and roots, and because most strawbery crown moth larvae are established in these areas by mid-August, applying insecticides to control this pest is not recommended after the first week in August. Use pheromone traps to determine the first consistent emergence of moths in late spring (usually from the last of May to early June depending on location). About 10 to 14 days later, apply either azinphos-methyl or endosulfan in at least 200 gal water/a as a high-pressure spray to saturate crowns. Two weeks later, if plants have not been topped, apply the insecticide not used for the first application. If plants have been topped by this time, use Lorsban as described below.

Thrips
Frankliniella spp.

Pest description: Adults are generally yellowish-brown to straw colored and less than an eighth of an inch long. Winged adults have four wings which are long and narrow with a fringe of long hairs on the margins. Nymphs resemble adults except in size and lack of wings.

Crop damage: Adults and nymphs feed by rasping. Feeding on ripening fruit can cause bronzing and cracking of the fruit.

Chemical control:

Biological control:

Twospotted Spider Mite
Tetranychus urticae

Pest description: Adult mites are about 0.02 inch long. They have eight legs and are light tan or greenish in color with a dark spot on each side of their back. In fall and again in spring, overwintering forms appear as bright orange globules.

Crop Damage: Mites feed by sucking the contents out of leaf cells, causing a mottling of the leaves. They feed mostly on older leaves, which reduces plant vigor and can negatively affect yield.

Chemical control:
Repeat applications may be necessary to control mite populations. Rotate chemistries to avoid restistance. Apply in sufficient water and at sufficient pressure to coat undersides of leaves.

Biological Control:

The mild, moist conditions in Oregon's Willamette Valley are ideal for disease development caused by various fungal organisms. More than 90% of Oregon's strawberry acreage is treated with a fungicide at least once but, more often, two to three times per season (1). Grey mold (fruit rot), caused by Botrytis cinerea, is the most wide-spread fungal disease (7). It causes lower quality fruit and/or reduced marketable yields, and requires several (two to five) applications of a fungcide per season for adequate control. Tank mixing or rotation with fungicides that have different modes of action are critical in a grey mold control program to prevent likelihood of disease resistance. Red stele (root rot), caused by Phytophthora fragariae, is another serious, wide-spread disease that causes reduced plant vigor and, subsequently, reduced yields. Severely infected plants wilt and die (10).

Black Root Rot
Rhizoctonia sp., Fusarium spp., and Ramularia spp

Black root rot is a complex interaction of fungi, nematodes, weather, and poor soil characteristics. Organisms or factors involved in one area may not be involved in others. Some of these organisms are native soil fungi and survive indefinitely in soil. Root-lesion nematodes are frequently involved in black root rot.

Symptoms: Symptoms include black discolorations on roots; the entire root or all but the core often darken, look unhealthy, and lack new growth. Foliage is reduced in size, has poor color, and wilts in warm weather. Although many roots rot away completely, they lack the red core discoloration typical of red stele.
Chemical control: Preplant fumigation.

Common Leaf Spot
Mycosphaerella fragariae(asexual: Ramularia brunnea)

This fungus overwinters on old, infected leaves and as sclerotia. Conidia are produced abundantly in lesions on infected leaves. Sclerotia in dead leaf material produce conidia in the spring. Conidia are rain splashed to healthy tissues. Only young leaf tissue is suceptible to infection and then, only after a minimum of 12 hours of leaf wetness. Long wet periods (several days) and warm temperatures (over 50°F) favor disease development in the spring and in summer after renovation. 'Olympus' and 'Shuksan' are very susceptible.

Symptoms: Foliage is at first dark red or purplish, gradually becoming grayish or almost white with age. Fully developed spots are about 0.12 inch in diameter, with a whitish center and reddish margin. They are scattered widely over the leaf surface, reducing leaf function. Infections occur in moist weather and are most severe in spring and fall.
The fungus also can infect fruit in what is called black seed disease. Berries usually have one or two spots but may have as many as 10. Spots are brownish black, hard, and leathery and appear on one to several achenes. Fruit does not rot but discolors under the spot.
Chemical control:

Cultural control: Removing foliage after harvest reduces inoculum in the field. Mow leaves of June-bearing plants 0.5 inch above the crown after harvest. Leaf spot can still be a problem after renovation unless supplemented with chemical protection.

Grey mold
Botrytis cinerea

This fungus overwinters as sclerotia or dormant mycelia in old leaves, petioles, and mummified fruit. Conidia from within the planting are the principal source of inoculum and are produced readily and for a long time on diseased plant material. Conidia readily infect the petals, stamens and pistals but not sepals. Mycelium then invades the developing fruit. Symptoms are generally delayed until fruit maturity and then progresses rapidly. No cultivar is immune, and even the least susceptible sustain considerable losses when environmental conditions favor disease development. The disease is more severe in high-density, double-row beds.
Symptoms: Blossom blight is characterized by petals and pedicels turning brown. The entire blossom may die. Fruit rot symptoms may occur on any portion of the fruit. They frequently develop at the calyx end and in tissues contiguous with rotting fruit or diseased flowers. Affected tissue turns light to medium brown. Lesions in green or white fruit develop slowly. The fruit may be misshapen as it enlarges. Fruit rot expands rapidly near harvest. In advanced stages, the fungus produces a gray mold over the fruit surface. Rot may not develop until after fruit is harvested.

Chemical control:
Apply during bloom period. Start at first bloom; repeat at regular intervals, especially during wet weather. Applications during fruit ripening are of questionable value. Without floral applications, fruit ripening applications are worthless.

Biological control:

Cultural control:

Leaf Scorch
Diplocarpon earlianum (asexual: Marssonia fragariae)

This fungus overwinters on old infected leaves. Conidia are produced in acervuli and are splashed to healthy tissue. Conidia are sticky and can directly penetrate the leaf cuticle. During spring rains, spores from just a few diseased plants can multiply and spread through the entire planting. This disease is generally more severe in second- and third-year fields.

Symptoms: Small, dark purple spots develop on upper leaf surfaces and remain dark purple. A white center never forms, as with common leaf spot. Spots have an irregular outline. If numerous, spots run together, and leaves appear scorched. In severe cases, foliage is reduced considerably, and plants may be stunted. Infected fruit has elongated, slightly sunken, reddish areas or streaks, but the marks disappear as the fruit ripens.

Chemical control: Tolerant strains of some fungi have become troublesome when Benlate or Topsin M is used exclusively in a spray schedule. To reduce the possibility of tolerance, tank-mix Benlate with fungicides having a different mode of action. Do not mix Benlate and Topsin M; they have the same mode of action.

Cultural control:

Powdery Mildew
Sphaerotheca macularis f. sp. Fragariae

This fungus overwinters on infected plant tissue, including living leaves. This fungus is favored by conditions that produce high humidity but dry leaves. It is a highly specialized pathogen that forms a close association with the host. Conditions that favor the host also favor the pathogen. Much of the fungus remains on the outside of infected plant parts but sends in rootlike structures, haustoria, to obtain nutrients. The white growth seen is composed of both mycelium and fungal spores.

Symptoms: Edges of infected leaflets curl up, exposing undersides that often are reddened and coated with a grayish white powdery mildew fungus. Diseased leaves later turn purplish or red. In irrigated fields, the fungus also may attack fruit. Some day-neutral cultivars are susceptible to fruit infection in fall even though leaves may appear healthy.

Cultural control:

Chemical control: The disease needs to be controlled on highly susceptible cultivars after summer renovation so plants remain vigorous until they cease growth and go dormant in late fall.

Red Stele
Phytophthora fragariae var. fragariae

The causal agent of red stele is a soil-infesting fungus-like microorganism that may live many years in the soil. It is active in cool, wet weather. It attacks roots soon after fall rains begin and remains active through winter, spreading most rapidly where drainage is poor or in heavier soils. Well-drained fields are less often attacked, but low areas often show typical red stele infection. Of the seven races of this organism that have been described, five have been reported from Oregon.

Symptoms: The core or stele of diseased roots in winter and spring has a reddish pink tinge gradually turning a cinnamon-brown while the root's outer cortex stays white. Ultimately the diseased core turns black. Most of the plant's main roots show the symptom, but after May it is difficult to see. Lateral roots are quickly destroyed, giving main roots a rat tail appearance. Severely diseased plants are stunted, and under certain conditions the youngest leaves take on a bluish-green tinge and lack normal glossiness. Older leaves generally turn red, orange, or yellow. Such plants eventually wilt and die.

Chemical control: Alternate between chemicals with different modes of action to prevent or delay building up resistant microorganisms. Red stele microorganisms resistant to Ridomil have been detected in the major strawberry-growing areas of the Willamette Valley of Oregon.

Cultural control:

Verticillium Wilt
Verticillium dahliae and V. albo-atrum

This soil-borne fungus can live many years in soil. Isolates that can attack strawberry have a wide host range, so it is not advisable to plant strawberry after solanaceous (potato family) or small fruit crops that have shown evidence of the disease. Many cultivars derived from resistant clones of Fragaria chiloensis, F. virginiana, and F. virginiana subsp. glauca are resistant to strains of Verticillium.

Symptoms: Individual plants wilt, sometimes in patches in the field. Plants are most severely affected in their first year. Older leaves wilt and tend to curl up along the midvein. Inner (younger) leaves tend to remain green although stunted. Plants often are stunted, dry, and flattened with small yellowish leaves, especially as fruit ripens. Brownish streaks occur in vascular tissue of crown roots or at the base of the petiole.

Chemical control:
Preplant fumigation:

Cultural control:

Virus Diseases

Strawberry crinkle virus, Strawberry mottle virus, Strawberry mild yellow-edge virus, and Strawberry vein-banding virus commonly infect strawberry plants in Oregon. These viruses are transmitted by aphids (see above section on insect control). Tomato ringspot virus is spread by the dagger nematode (see nematode control section, below). Tobacco streak virus and pallidosis disease also are found in Oregon strawberry fields but they spread naturally by unknown means.
Symptoms: There are few if any diagnostic symptoms of specific viruses in strawberry cultivars commonly planted in Oregon. Some general symptoms are described below:
Tomato ringspot virus: stunting and sometimes death. Susceptible cultivars are Benton, Hood, Olympus, Puget Beauty, Rainier, Shuksan, and Totem. 'Northwest' appears to be immune.
Aphid-transmitted viruses: vigor and yield decrease, but usually the only distinctive symptoms are dwarfing, leaf cupping, and yellowing. 'Totem', 'Shuswap', and 'Sumas' are the most virus tolerant cultivars; 'Hood' is the most sensitive. The former cultivars become infected as readily as others but usually do not show symptoms unless infected by three of the viruses.
Tobacco streak virus: loss of vigor and yield without distinctive symptoms.
Pallidosis agent: increases the severity of many aphid-transmitted viruses.

Cultural control:

Several different nematodes are commonly found in strawberry plantings (10). Their feeding on roots can stunt plants and reduce runner production. Of greater concern, however, is the potential for them to vector virus diseases. Sampling for nematodes prior to planting is critical as any chemical controls are pre-plant only. Growers are advised to avoid nematode infested areas, if possible.

Dagger Nematode
Xiphinema americnum and related species

Dagger nematodes are vectors of Tomato ringspot virus. They are migratory found only in soil. As virus vectors, they can be damaging at very low population levels. Dagger nematode populations may be very low in late summer when other nematodes are abundant. The best time for sampling is December to April.

Symptoms: In the absence of the virus, the nematodes may cause sunken reddish brown lesions on roots. Feeding can reduce the root system, which can stunt growth and reduce runner production. If Tomato ringspot virus is vectored, the plants will appear stunted and some areas of the field will have dead plants.

Chemical control:
Preplant soil fumigation is best for controlling this nematode. Apply in fall for planting the next spring.

Cultural control:

Root-knot nematode
Meloidogyne hapla

This nematode lives in soil and attacks many other kinds of plants. Root-knot nematodes are sedentary endoparasites; only second-stage juveniles (the infective stage) and adult males (which may be rare) are in soil.

Symptoms: Plants look unthrifty and off-color. Roots have large or small galls. Sampling should include both soil and roots.

Chemical control:
Preplant soil fumigation. Apply in the fall before planting the next spring.

Cultural control:

Root-Lesion Nematode
Pratylenchus penetrans and P. crenatus

This nematode lives in soil. Legumes such as clover, alfalfa, and vetch often harbor large populations of root-lesion nematodes, which may affect future strawberry plantings. The number of nematodes in the soil can be a rough guide to possible plant damage. Factors such as crop age, planting frequency, presence of other diseases and pests, and adverse growing conditions influence the effect on plant growth. In some cases, 300 nematodes/100 g of soil affect plant growth, but much higher populations often have little effect. Root-lesion nematodes are migratory endoparasites; part of the population is in soil and part in the roots at all times.

Symptoms: Infected plants are dwarfed, off-color, and grow poorly. Damage is frequently seen as spots in the field. Roots have brown lesions. Include soil and roots when sampling. Populations are relatively low through winter and spring but increase rapidly through summer. Before planting strawberries, it is best to sample in late summer.

Chemical control:
Preplant soil fumigation:

Cultural control:

Stem and Bulb Nematode
Ditylenchus dipsaci

This nematode infects aboveground portions of plants but is rarely found in strawberries. Take soil samples before planting strawberries if the field has a history of stem nematode problems. If this nematode is suspected in an established plant, only the affected crowns need to be submitted for testing.

Symptoms: Plants are stunted from the crown with short, thick petioles. The symptoms are most evident in cool, wet springs.

Cultural control:

Weed competition in strawberry fields can reduce plant vigor and, subsequently, yield. Approximately 80% of all strawberry acreage is treated with an herbicide (1). Hand weeding in the plant row and cultivation between the rows are also common practices, usually in conjunction with herbicide applications (6). 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 are renovated by mowing old leaves, cultivating row middles, and sometimes applying an herbicide. In mid-August, plants are fertilized and watered to enhance flower bud development.

Although strawberries are rotated with other crops every 3 to 5 years, weed shifts or the incidence of tolerant species often occur with repeated use of the same or similar weed control practices. 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 (12). Sulfentrazone (Spartan 4F) has used under Section 18 emergency exemption registration for the past two year for control of many broadleaf weeds, especially those seemingly resistant to napropamide (Devrinol) and simazine, and some grass weeds,. Spartan has been allowed for use during three distinct periods: Pre-plant, after renovation before new growth resumes, and during winter dormancy.

New Plantings

Glyposate

Formulation: Roundup UltraMax RT
Application Type and Timing: Post emergence. Used for site preparation; apply pre-plant only and at least three days before transplanting.
Application Rate: Rate depends on weed to be controlled. Consult label. (supplemental label allows use in all Oregon counties.)
PHI: NA
REI: 4 hours

Napropamide

Formulation: Devrinol 50 DF
Application Type and Timing: Preemergence. Apply before weeds germinate or after cultivating to remove growing weeds. Do not apply from bloom through harvest.
Application Rate: 4 lb ai/A
PHI: Unavailable
REI: 12 hours
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. Application of 2 lb ai/A at planting at planting can minimize root pruning and pegging problems; apply an additional 2 lb ai/A in fall.

Pendimethalin

Formulation: Prowl 3.3 EC
Application Type and Timing: Preemergence. Apply before transplanting strawberries.
Application Rate: 0.75 to 1.65 lb ai/A (1.8 to 4.0 pints/A)
PHI: 365 days
REI: 24 hours
Remarks: Non-bearing strawberries, only. Most effective when incorporated in weed emergence zone by rainfall or irrigation within 7 days. Stunting, reduced growth, or reduction in daughter plants may occur. 24c registration.

DCPA

Formulation: Dacthal W-75
Application Type and Timing: Preemergence. Apply soon after transplanting or preplant incorporate.
Application Rate: 9 lb ai/A
PHI: NA
REI: 12 hours
Remarks: Applications west of the Cascades usually perform erratically.

Lactofen

Formulation: Cobra
Application Type and Timing: Preemergence. Apply immediately before or after transplanting or within 48 hours after transplanting if soil is placed over plants to minimize contact and possible injury.
Application Rate: 0.25 to 0.38 lb ai/A (16 to 24 ounces product/A)
PHI: 365 days
REI: 12 hours
Remarks: Non-bearing strawberries, only. Activate with 0.25 to 0.5-inch water within 48 hours. Grasses are not controlled. 24c registration.

Sethoxydim

Formulation: Poast
Application Type and Timing: Post emergence. Apply at optimum weed growth stage listed on the label.
Application Rate: 0.19 to 0.478 lb ai/A (1 to 2.5 pints product/A)
PHI: 7 days
REI: 12 hours
Remarks: Controls grasses only. Control often is erratic on grasses that are stunted or stressed from drought, high temperatures, or low fertility. Resistant grasses include annual bluegrass and all fine fescues, but quackgrass can be suppressed. Addition of a non-phytotoxic crop oil concentrate (at 2 pints/A) will improve leaf absorption. Do not exceed 2.5 pints of product per acre per season.

Clethodim

Formulation: Prism, Select 2 EC
Application Type and Timing: Post emergence. Apply to actively growing grass weeds.
Application Rate: 0.094 to 0.125 lb ai/A (13 to 17 fl oz/ Prism; 6 to 8 fl oz/A Select)
PHI: 4 days
REI: 24 hours
Remarks: Controls grasses only. Effective on annual bluegrass. Limited observations suggest that April treatments my cause slight cupping and browning of petals or blossoms. Addition of a non-phytotoxic crop oil concentrate (at 1%v/v) will improve leaf absorption.

Established Plantings
(Early Fall or Winter Applications)

Simazine

Formulation: Simazine 90 WDG or 90 DF, Princep Caliber 90, Simazine 4L
Application Type and Timing: Preemergence. Apply in October or November and activate with rain. Apply only once per year
Application Rate: 1.0 lb ai/A
PHI: NA
REI: 12 hours
Remarks: Established weed seedlings will not be controlled. Do not use on sandy or coarse soils.

Terbacil

Formulation: Sinbar
Application Type and Timing: Preemergence. Apply to plants that have been established in the field for at least six months. Apply during late fall or winter, when strawberry plants are not actively growing.
Application Rate: 0.1 to 0.3 lb ai/A
PHI: NA
REI: 12 hours
Remarks: Weeds greater than one inch tall or wide will not be controlled. Treatments may reduce plant vigor. Do not use on sandy, loamy sands, gravelly soils or soils containing less than 2% organic matter. Avoid use for 2 years when replanting is anticipated; consult label for recropping information. Do not apply more than 0.5 lb Sinbar (0.4 lb ai) per growing season.

Napropamide

Formulation: Devrinol 50 DF
Application Type and Timing: Preemergence. Apply fall through early spring before weeds emerge, preferably in November or December.
Application Rate: 4 lb ai/A
PHI: Unavailable
REI: 12 hours
Remarks: Due to possible carryover in wheat rotations, use other weed control practices the final year of strawberry production or deep plow to dilute the soil residue.

DCPA

Formulation: Dacthal W-75
Application Type and Timing: Preemergence. Apply in fall or early spring to control late summer weeds.
Application Rate: 6 to 9 lb ai/A
PHI: NA
REI: 12 hours
Remarks: Applications west of the Cascades usually perform erratically.

Sethoxydim

Formulation: Poast
Application Type and Timing: Post emergence. Apply at optimum weed growth stage listed on the label.
Application Rate: 0.38 to 0.48 lb ai/A (2 to 2.5 pints/A Poast)
PHI: 7 days
REI: 12 hours
Remarks: Controls grasses only. Control often is erratic on grasses that are stunted or stressed from drought, high temperatures, or low fertility. Resistant grasses include annual bluegrass and all fine fescues, but quackgrass can be suppressed. Addition of a non-phytotoxic crop oil concentrate (at 2 pints/A) will improve leaf absorption. Do not exceed 2.5 pints of product per acre per season.

Clethodim

Formulation: Prism, Select 2 EC
Application Type and Timing: Post emergence. Apply to actively growing grass weeds.
Application Rate: 0.094 to 0.125 lb ai/A (13 to 17 fl oz/ Prism; 6 to 8 fl oz/A Select)
PHI: 4 days
REI: 24 hours
Remarks: Controls grasses only. Effective on annual bluegrass. Addition of a non-phytotoxic crop oil concentrate (at 1%v/v) will improve leaf absorption.

2,4-D Amine

Formulation: Formula 40
Application Type and Timing: Post emergence. Apply only when strawberries are fully dormant during winter.
Application Rate: 0.95 to 1.425 lb ae/A
PHI: NA
REI: 48 hours
Remarks: Controls broadleaf weeds only. Injury may result from variations in climatic conditions, stage of strawberry growth, or susceptibility of varieties. Use only in fields with extreme infestations of established broadleaf weeds when other weed control alternatives are lacking. The Formula 40 label states,"Do not apply unless injury to the crop is acceptable".

 

Established Plantings
(During bed renovation in summer)

Simazine

Formulation: Simazine 90 WDG or 90 DF, Princep Caliber 90, Simazine 4L
Application Type and Timing: Preemergence. Apply after bed renovation and first irrigation, followed with additional 0.5 inch irrigation to activate the herbicide. Apply only once per year.
Application Rate: 1.0 lb ai/A
PHI: NA
REI: 12 hours
Remarks: Established weed seedlings will not be controlled. Do not use on sandy or coarse soils. In summer, simazine is only about half as active as in winter applications.

Terbacil

Formulation: Sinbar
Application Type and Timing: Preemergence. Apply to plants that have been established in the field for at least six months. Apply before new strawberry growth begins and before weeds are more than 1 inch tall or wide.
Application Rate: 0.1 to 0.3 lb ai/A
PHI: NA
REI: 12 hours
Remarks: Make a split application (summer and fall/winter), using a lower rate after bed renovation in summer; do not apply more than 0.5 lb Sinbar (0.4 lb ai) per growing season. Weeds greater than one inch tall or wide will not be controlled. Treatments may reduce plant vigor. Do not use on sandy, loamy sands, gravelly soils or soils containing less than 2% organic matter. Avoid use for 2 years when replanting is anticipated;consult label for recropping information.

Napropamide

Formulation: Devrinol 50 DF
Application Type and Timing: Preemergence. Apply to weed-free soil after bed renovation.
Application Rate: 4 lb ai/A
PHI: Unavailable
REI: 12 hours
Remarks: Applications during the growing season may delay or inhibit rooting (pegging) of runners.

Paraquat

Formulation: Gramoxone Max, Gramoxone Extra
Application Type and Timing: Post emergence. Apply as a directed spray between rows using shields to prevent spray contact with crop.
Application Rate: 0.5 lb ai/A (1.3 pints/A Gramoxone Max; 1.5 pints/A Gramoxone Extra)
PHI: 21
REI: 12 hours
Remarks: Add a nonionic surfactant or crop oil concentrate as label directs; avoid anionic formulations that react to form insoluble precipitates. Do not apply more than three times a year. Restricted use pesticide.

2,4-D Amine

Formulation: Formula 40
Application Type and Timing: Post emergence. Apply after harvest when no new growth is visible but before flower buds begin to form.
Application Rate: 0.95 to 1.425 lb ae/A
PHI: NA
REI: 48 hours
Remarks: Controls broadleaf weeds only. Injury may result from variations in climatic conditions, stage of strawberry growth, or susceptibility of varieties. Use only in fields with extreme infestations of established broadleaf weeds when other weed control alternatives are lacking. The Formula 40 label states, "Do not apply unless injury to the crop is acceptable".

Sethoxydim

Formulation: Poast
Application Type and Timing: Post emergence. Apply at optimum weed growth stage listed on the label.
Application Rate: 0.38 to 0.48 lb ai/A (2 to 2.5 pints/A Poast)
PHI: 7 days
REI: 12 hours
Remarks: Controls grasses only. Control often is erratic on grasses that are stunted or stressed from drought, high temperatures, or low fertility. Resistant grasses include annual bluegrass and all fine fescues, but quackgrass can be suppressed. Addition of a non-phytotoxic crop oil concentrate (at 2 pints/A) will improve leaf absorption. Do not exceed 2.5 pints of product per acre per season.

Clethodim

Formulation: Prism, Select 2 EC
Application Type and Timing: Post emergence. Apply to actively growing grass weeds.
Application Rate: 0.094 to 0.125 lb ai/A (13 to 17 fl oz/ Prism; 6 to 8 fl oz/A Select)
PHI: 4 days
REI: 24 hours
Remarks: Controls grasses only. Effective on annual bluegrass. Addition of a non-phytotoxic crop oil concentrate (at 1%v/v) will improve leaf absorption.

Joe DeFrancesco
Dept. of Entomology
Oregon State University
2046 Cordley Hall
Corvallis, OR 97331-2907
541/737-0718
defrancj@bcc.orst.edu

Jim Gill
NORPAC Foods
P.O. Box 458
Stayton, OR 97383-0458
503/291-1510

Diane Kaufman
OSU/North Willamette Research and Extension Center
15210 NE Miley Road
Aurora, OR 97002
503/678-1264 x23
Diane.Kaufman@orst.edu

Philip Gütt
Executive Director
Oregon Strawberry Commission
4845B SW Dresden
Corvallis, OR 97333

1. Agricultural Chemical Usage, 2000 Vegetable Crops Summary. National Agricultural Statistics Service. U.S. Department of Agriculture. Online. http://usda.mannlib.cornell.edu/reports/nassr/other/pcu-bb/agcv0701.txt
2. Berry, Ralph E., Insects and Mites of Economic Importance in the Pacific Northwest. 1978. OSU Book Store Inc., 189 pp.
3. Crop Production Summary for 2001, Non-citrus Fruits and Nuts. U.S. Department of Agriculture. Online. http://usda.mannlib.cornell.edu/reports/nassr/fruit/pnf-bb/ncit0702.txt
4. Enterprise Budget, Strawberries, Willamette Valley Region. EM 8463. Oregon State University Extension Service, Corvallis, OR. March 1991.
   
5. Gill, Jim, NORPAC Foods Inc., Stayton, OR. Personal communication.
6. Kaufman, Diane. Oregon State University Extension Service. Small Fruits District Extension Agent. Personal Communication.
   
7. Markle, G.M.; Baron, J.J.; Schneider, B.A. Food and Feed Crops of the United States, Second Edition. Meister Publishing Co., Willoughby, OH. 1998.
8. Oregon Agricultural Information Network. Oregon State University Extension Service. Online. http://ludwig.arec.orst.edu/oain/SelYearCommodity.asp?ddopt=2
   
9. Oregon Strawberry Commission. Online. http://www.oregon-strawberries.org
10. 10. Pacific Northwest Disease Management Handbook. 2002. Extension Services of Oregon State University, Washington State University, and the University of Idaho.
11. 11. Pacific Northwest Insect Management Handbook. 2002. Extension Services of Oregon State University, Washington State University, and the University of Idaho.
12. 12. Pacific Northwest Weed Management Handbook. 2002. Extension Services of Oregon State University, Washington State University, and the University of Idaho.

 

 

Acknowledgements

This crop profile was prepared by J.DeFrancesco, Department of Entomology, W. Parrott, and J. Jenkins, Agricultural Chemistry Extension, Department of Environmental and Molecular Toxicology, Oregon State University.