ON AUGUST 14, an employee of Washington State's gypsy moth eradication program found a male moth caught in a female-pheromone-baited trap near rural Vader, Washington, about halfway between Centralia and Kelso. As is standard practice when these destructive leaf-chomping pests are detected, more traps were distributed around the first find site. Before early September, when the moth breeding season winds down, 72 moths had been trapped in the area and their apparent origin discovered: Six "egg masses" were found in apple trees growing in a yard on the outskirts of the unincorporated village.
Seventy-two moths definitely rates in the eradication program's books as an "infestation," so folks living along the I-5 corridor in southern Lewis and northern Cowlitz County can expect to be the focus of the state Department of Agriculture's federally subsidized antimoth aerial spraying program next spring.
For 20 years and more, the battle to prevent the European gypsy moth from taking up permanent residence in the Northwest has been waged by sprinkling billions of spores of a soil bacterium known as btk over the affected area. Some of the spores infect moth larvae and kill them by destroying their digestive organs.
Only recently has the government's assertion that btk is harmless to humans, other mammals, and beneficial insect species come into question. Earlier this summer, plans to spray densely populated Ballard and Magnolia (to counteract an infestation consisting of one moth and one egg-mass) raised public awareness fast, and, thanks to state experts' refusal to consider any alternative to spraying, generated protests even among state legislators.
Apart from the Vader outbreak, the rest of the state racked up only about a dozen moth sightings this year in nine widely scattered locations, including Renton, Tukwila, and Sumner. One moth, or even several, may not count as an infestation—unless the moth in question belongs to the Asian subvariety of the species, like the one that set off the uproar in Seattle last year.
Asian gypsy moths, native to Korea and Siberia, are particularly feared for two reasons: The females can fly—unlike those of the European variety, which just stay put and release pheromones while waiting for a male to find them—and thereby spread an infestation much more quickly. And Asian moths have a taste not just for leafy trees but for conifers, making them much more of a threat to Northwest forests with their omnipresent (and economically valuable) evergreens.
No one will know whether any of the moths trapped this summer are the Asian type for several weeks yet: The difference between varieties is distinguishable only by laborious and expensive genetic analysis, now taking place in the USDA's moth lab on Cape Cod. But if even one of this summer's moths is Asian, expect the state's response to be vigorous, thorough, and implacable.
But expect the resistance to blanket spraying to be stronger than ever, too, even in bucolic Vader. The government's claim that btk is harmless to children and other living things is based less on evidence than lack of evidence to the contrary. State and federal authorities, who get more of their data from the pesticide industry than their own public health experts, have given gentler, less aggressive methods of moth control short shrift. If Ag elects to spray in April 2001, it will first have to get past the substantial minority of state House and Senate members pissed off last spring by the Department's refusal to deal promptly and openly with their constituents' concerns.
More on moths:
-The moths' revenge
-Bugged in Ballard
-Nuke the moths!