European gypsy moth larvae feed on trees and shrubs. Washington’s Department of Agriculture will spray 1,300 acres to stop an outbreak.

About 1,300 acres in northwest Washington likely will be sprayed with an insecticide next spring to stop an outbreak of gypsy moths, including a type native to Asia never before detected in the U.S.

The Washington State Department of Agriculture said it tentatively plans to release Bacillus thuringiensis var. kurstaki over Woodway, a small city on Puget Sound, and Boulevard Bluffs, an Everett neighborhood. Both places are in Snohomish County.

An Hokkaido gypsy moth was trapped in Woodway this summer. It was the first Hokkaido moth caught in the U.S. It feeds predominantly on larch trees in its native habitat, according to the department.

Three hybrid Asian gypsy moths were caught in Boulevard Bluffs.

Gypsy moths native to Asia are more mobile than European varieties and are considered more of a danger to spread.

Statewide, the department trapped 14 gypsy moths, a relatively low number. The department caught 11 European gypsy moths.

Before finalizing plans to spray, the department will conduct environmental reviews and consult with other agencies, including the USDA. The department said it will explain its plan to residents at open houses.

European gypsy moths defoliate a wide variety of trees and shrubs. They are established throughout the East and Great Lakes. Western states have been successful in eradicating incipient populations.

Washington has sprayed for gypsy moths most years since 1979. To cover large areas, the agriculture department contracts with an aviation company to spray from the air.

Gypsy moths spread by laying eggs on personal belongings or ships. Eradication campaigns take place in the spring to kill emerging caterpillars.