State entomologists say European gypsy moth eggs found in the parking lot of South Hill Mall in Puyallup could grow into a destructive force if they’re not eradicated, and officials want to spray trees and plants there in the spring to prevent the insect from making a permanent home.
They propose using Bacillus thuringiensis var. kurstaki, a bacteria that’s found naturally and is used throughout the United States to eradicate gypsy moths, said Mike Louisell, a spokesman for the state Department of Agriculture. He said numerous studies have found that the health risk for humans is very low.
There are no homes in the 29-acre area that is proposed to be treated, he said.
“If we do not take action to eradicate this small population, it could quickly become a very serious situation where they’ve reproduced enough that the caterpillars could do damage to the environment,” Louisell said.
There also could be economic ramifications, with quarantines of the timber, nursery and Christmas tree industries, said Jim Marra, managing entomologist for the state agriculture department.
It’s the caterpillars that do the damage, eating the leaves of trees and plants, Marra said. They can defoliate thousands, even millions, of acres a year, he said.
There are permanent gypsy moth populations in 19 states in the Northeast and Midwest. Washington doesn’t have any permanent populations, but the moths have been detected in the state annually since 1977, the agriculture department said. The eggs usually are transported after they’re attached to cars or other belongings.
Marra said as many as 25,000 traps are put out every year, enticing the male moths with pheromones. This year, 13 moths were caught, mostly in Pierce County.
Officials found about three egg masses in vegetation at the mall on South Meridian, Marra said. Each mass can hold hundreds of eggs, he said.
The agriculture department is proposing three to five insecticide applications in April or May. Officials must wait until then so the eggs have time to hatch; the caterpillars have to ingest the insecticide, Marra said.
The insecticide would be applied to the trees and plants after mall business hours. David Montevideo, mall property manager, said he is working with officials from the agriculture department.
The agriculture department has done 85 gypsy moth eradications since 1979, Louisell said.
The agriculture department is preparing documents outlining the pros and cons of spraying that will be available for public review before a final decision about moving forward is made. A community meeting is planned in late January. The time and date haven’t been announced.
More information is at tinyurl.com/2d6ubst.
Sara Schilling: 253-552-7058 sara.schilling@thenewstribune.com
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