By STEVE BROWN
OLYMPIA -- The Washington State Department of Agriculture will begin gypsy moth caterpillar eradication treatments in Tukwila, south of Seattle, this week.
The WSDA and the USDA jointly approved the project after a 30-day review period.
The exact date of the first treatment depends on larval development, leaf development and weather conditions. Three to five treatments will be conducted at the 10.5-acre site, three to 14 days apart. Operators will use ground equipment to apply a biological insecticide to trees, shrubs and other foliage that may harbor gypsy moth caterpillars.
During last summer's annual statewide trapping program, WSDA trappers caught 27 gypsy moths, 25 of them in Tukwila. Entomologists also discovered 11 gypsy moth egg masses there, indicating that a reproducing population is present. Between 500 and 1,000 caterpillars can emerge from a single egg mass.
"The large number of catches in Tukwila is one of the largest we have seen in recent years," Jim Marra, managing entomologist for WSDA, said in a news release. "Gypsy moth has defoliated millions of acres of forest in recent years across the Northeast and Midwest. If left unchecked, gypsy moths would devastate Washington's forests."
In July the eradication effort will continue with an aircraft flyover to treat a surrounding 180-acre site with the pheromone disparlure, which disrupts mating behavior in adult gypsy moths.
In June, the WSDA will begin treatment on another pest, the noxious weed spartina, which disrupts ecosystems in saltwater estuaries and can harm the state's shellfish industry.
The WSDA will cooperate with universities, interested groups, private landowners and local, state, federal and tribal governments to survey more than 80,000 acres of estuaries and 1,000 miles of shoreline in 14 counties to determine the extent of spartina infestation. They will dig out small infestations and treat larger sites with the herbicides glyphosate and imazapyr.