Strawberry Fragaria (Rosaceae) Fast Facts: Acres in Washington: 1500 Percent U.S. Acreage: 3% Per Acre Value: $2500-$4000 Number of Growers: 64 Value of Production in Washington: $3.7-$6 Million Percent of Value of U.S. Production: less than 1% Strawberries are the 35th most valuable commodity in the state Description of crop: In Washington, strawberries are available for the fresh market from the last week in May, when harvest begins in southern Washington, to the end of June when harvest ends in northern Washington. Although some varieties of strawberries are ever-bearing, Washington has little, if any, acreage of this type of strawberry. Strawberries take one to two years to reach production,. They are started from transplants propagated from the runners of a “mother” plant. There are two propagating nurseries in the Pacific Northwest, both in Washington. One is near Burlington, and one is near Olympia. Thus, 75 percent to 85 percent of Washington strawberries are propagated in Washington, and the remaining plants are obtained usually from California. A field of strawberries grown for the processing market will remain in production for one to three years. A field grown for the fresh market will last one to two years. Damage from root weevils is the primary cause of field failure. Key pests: The most severe insect pests are root weevils. These include strawberry root weevil, rough strawberry root weevil, black vine weevil, woods weevil and obscure root weevil. Other insect pests include spider mites, cyclamen mite and strawberry aphid. Cyclamen mite has been an increasing problem, and aphids are important because they transmit several viruses including mottle virus, crinkle virus, mild yellow-edge virus and vein banding virus. Lygus are a pest on the fresh market or day neutral varieties. Disease problems include botrytis fruit rot, which is a major problem and is also known as gray mold, and red stele root rot. Powdery mildew can be a major problem and seems to be becoming more serious. Weeds, including clovers, chickweed, shepherdspurse and groundsel, are significant pests. Nematodes, both root lesion and dagger, can be problems but are controlled with pre-plant fumigation. Key pesticides: Carbofuran was used occasionally to control weevils, but this use has gone away.. In 1993 and 1994, a Secton 18 exemption was granted to use bifenthrin for control of weevils. Mites are an occasional major pest. Spider mites are controlled dicofol or fenbutatin-oxide. Neither insecticide provides excellent control and some spider mites are showing resistance to dicofol. Endosulfan and dicofol are used for cyclamen mite control; however, in California, some mites are developing resistance to miticides. Aphids are controlled effectively with bifentrin or chlorpyrifos. Metalxyl is used to control red stele root rot. Captan, benomyl, vinclozolin and iprodione are used for botrytis fruit rot: however, there is some resistance to benomyl, vinclozolin and iprodione. Chemicals used on gray mold are Switch, Elevate, Pristine, Thiram. Captan is the primary control for leaf diseases. Weeds are controlled with napropaide, simazine and some pendimethalin on new plantings. The industry has had a Section 18 for sulfentrazone (Spartan) for the last 4 years. In non-bearing strawberries with rye grass problems clethodim, sethoxydim or fluazifop-butyl is used. A newly registered herbicide, Chateau, will be used on a small basis until more is known. Critical pest control issues: Root weevils are a primary pest controlled almost exclusively by pesticides. There are no effective larvacides for root weevils. The loss of guthion has had a significant impact on options to control crown moth. Lack of options with any pesticide issue will contribute to resistance problems. Urbanization is an increasing and unrelenting problem for strawberry growers. Research into new varieties with resistance would be a great help. Totem is widely used as the variety for processing. Additional variety in processing type strawberries would aid in pest control issues. Research is being done regarding acceptable pest thresholds to cut down on costs and chemical loads. Scouting protocols and rotations are being studied and refined to further aid in accurate diagnosis and alternatives in pest management. Labor issues continue to be an issue for this crop. Expert contacts: Tom Peerbolt Peerbolt Crop Management 5261 North Princeton Portland, OR 97203 503 289 7287 Timothy W. Miller, PhD., Weed Scientist Washington State University Mount Vernon Northwestern Washington Research & Extension Center 16650 State Route 536 Mount Vernon, WA 98273 Location of production: Whatcom County has the most production. Production also takes place in Skagit, Clark, Spokane, Thurston and Walla Walla Counties. Pictures:
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