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
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
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
of production: Whatcom County has the most production. Production also takes place in
Skagit, Clark, Spokane, Thurston and Walla Walla Counties.