Battling the Buzz

County's aerial spray for mosquitoes happened fast


Boise residents, given 104 hours notice of an air assault on mosquitoes, scrambled this week to harvest or cover their crops, pick up their kids' outdoor toys, or get out of town.

On three nights this week, two small airplanes dropped a brand-name nerve agent over large swaths of the county, mainly in residential areas.

County officials say the plan will save people from the West Nile virus, but a researcher at Cornell University who has studied the disease says aerial spraying is a wholly political decision.

The high rate of West Nile virus infections in Idaho--the nation's highest this summer--is a concern, said David Pimentel, editor of the Encyclopedia of Pest Management.

"But then we ought to do it in a sound scientific manner and not just spray for political reasons," Pimentel said. "The politicians normally react that way to quiet the public."

On August 10, at the recommendation of county mosquito abatement director Brian Wilbur, Ada County commissioners declared a West Nile epidemic.

No members of the public were present at the last-minute emergency declaration meeting, according to county spokesman Rich Wright.

A week later commissioners signed a contract to spray Dibrom, commonly known as Naled, over about 50,000 acres of the county on two successive days.

Mary Rohlfing at the pesticide-free Morning Owl Farm returned to town Friday and did not have time to contact the county about the spraying.

"It seems absurd that there was no opportunity for input," Rohlfing said Sunday, taking a break from harvesting. She is trying to pick the ripe crops for her customers before the spraying. But, county spokesmen said, her farm is technically not in the spray zone.

The planes will not release the chemical over Zoo Boise or over four registered organic farms.

Wilbur said the county has been fighting West Nile with other tools all season. The district monitors and sprays mosquito larvae at about 1,800 sites. And with more than 80 complaints a day about mosquitoes, it sends out trucks to spray permethrin, a naturally-occurring chemical linked to breast cancer.

Under numerous state and national West Nile plans, Ada County's "multiple human cases"--68 as of Thursday--make it a Category 5 emergency situation. That calls for a stepped-up attack on the mosquitoes that carry the virus, mainly of the genus Culex, Wilbur said.

"The residents are telling us 'get out here and fog,'" Wilbur said. "We've done that and our Culex populations are still climbing."

Wilbur said the Dibrom spray that the planes will apply at very low doses is expected to cut down the Culex adult mosquito population by 90 percent, based on information from the Vector Disease Control, the Florida-based company contracted for the job.

Such an efficient kill is possible on a golf course, but unlikely in treed or residential areas, Pimental said, referring to his recent study and another from Harvard.

Even worse, Pimentel added, is that 75 to 90 percent of the pesticide drifts off into the environment at large.

Wilbur has said repeatedly that it is fine to leave windows open and air conditioning on and that he has no concerns about any health risks to people or to beneficial insects.

"What we go by is the chemical label and the chemical label does not give us any indication at all, it gives us no reservations at all," Wilbur said.

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