The Washington State Department of Agriculture will conduct the first of several treatments beginning April 16 to eradicate Asian and European gypsy moths, the highly destructive, invasive pests found in several Western Washington sites. Local sites include large areas of Tacoma’s tideflats, Fife, Edgewood and Milton.
In total, WSDA will treat about 10,500 acres with Btk (Bacillus thuringiensis var. kurstaki), which is approved for use on organic food crops and has been safely used in previous gypsy moth eradication projects for many years. April 16 is the tentative date of the first treatments at the ports of Tacoma and Vancouver, with other sites in areas of Seattle, Tacoma, Kent, Gig Harbor, Nisqually, Lacey, and Vancouver beginning treatment over the course of the following days.
These treatments are weather dependent, and rain or wind could force a change in the schedule. All applications are expected to be completed by mid-May. For the latest information on when treatments will occur, WSDA is advising people to visit agr.wa.gov/gypsymoth and sign up for e-mail, text, or robo call notifications issued the day before any application takes place.
Changes in scheduled treatments will also be shared via these notification systems. WSDA will use its twitter account, @WSDAgov, to provide timely information during operations. Postcards have been mailed to residents in the treatment areas advising them of the coming work and directing them to notification options. The public can also enter an address in a map on the agency website to verify whether their residence is within the treatment area. To eliminate the gypsy moth caterpillars, WSDA is planning to use Btk, a biological insecticide approved for use on organic food crops. Btk only targets caterpillars. WSDA has safely and effectively used it for more than 25 years, applying it to foliage that is then consumed by gypsy moth caterpillars.
Btk is not considered harmful to humans, pets, birds, fish, or bees. It is registered by the U.S. Environmental Protection Agency, which considers it a low-risk product. Btk is found naturally in the environment and has an excellent safety record. Although the risk is low, the Washington State Department of Health, as a precaution, recommends that people can minimize their exposure by remaining indoors during spraying and for 30 minutes afterwards. If you come into contact with the product, wash with soap and water.The treatments will be done by air and range from 25 minutes for the smallest treatment area in Capitol Hill to three hours for the largest treatment area in Tacoma. Each site will be treated at least three times with applications three to 10 days apart. WSDA anticipates all the work will be completed in about four weeks.
Btk treatments were recommended by a panel of gypsy moth experts WSDA consulted after last year’s large catch of 42 gypsy moths. The trapping results included 10 Asian gypsy moths, the most ever caught in Washington and the first Asian gypsy moths detected since 1999, when one Asian gypsy moth was found.
Gypsy moth is a serious threat to Washington’s environment, with the caterpillars feeding on host trees, plants and shrubs. The European gypsy moth has become permanently established in 20 states across the Northeast and Midwest, where it has defoliated millions of acres of forest lands and led to significant and costly trade restrictions for forest products. Because the female Asian gypsy moth can fly, it has a tremendous ability to rapidly increase its population, which could lead to the destruction of urban and natural forests.
If gypsy moth were to become established in Washington, it would threaten forest ecosystems, lead to quarantine restrictions on forest products and horticulture, and result in long-term increases in pesticide use by homeowners.
Visit the agency’s gypsy moth web page at agr.wa.gov/GypsyMoth to learn more or call the WSDA toll-free hotline at 1 (800) 443-6684.