The Washington State Department of Agriculture will begin gypsy moth caterpillar eradication treatments in late April or early May in Puyallup and Eatonville, Wash.
Approval came after a 30-day review period on two environmental documents. No public comments were received.
Gypsy moths don't pose a direct threat to agricultural crops, but an infestation can prompt a quarantine that would affect Washington farmers.
Mike Louisell, WSDA public information officer, said the invasive, destructive moth primarily affects deciduous trees, including oak, hawthorn, poplar, willow and maple.
"However, pear, apple and cherry trees are listed as a susceptible hosts for gypsy moth," he said. "It is conceivable that severe and repeated defoliation in untreated fruit trees could result in reduced fruit production or even tree death."
A growing population of the moth could result in a federal quarantine, which has been imposed on some states in the Midwest and on the East Coast. With Washington state's dependence on agricultural exports, "we do not want quarantines imposed on our state," Louisell said. "A population has never established in this state because of our aggressive program."
The exact date of the first treatment depends on larval development, leaf development and weather conditions. Three to five treatments will be conducted at each site, three to 14 days apart. Operators will use ground equipment to spray a biological insecticide (Bacillus thuringiensis var. kurstaki, or Btk), contacting trees, shrubs and other foliage that may harbor tiny gypsy moth caterpillars.
The Puyallup spraying involves a 43-acre site centered on the west side of the South Hill Mall parking lot. The treatments are to begin before dawn, long before stores open. The area is expanded from a 29-acre site treated at the shopping mall last spring.
The other project involves treating 13 acres in a residential area at Eatonville Highway and Hilligoss Lane, a new gypsy moth introduction. Residents will be notified prior to each treatment.
-- Steve Brown