sance aspects of this prolific critter.” Bacillus thuringienis (Bt)

sance aspects of this prolific critter.” Bacillus thuringienis (Bt) is a biological control. Like Dimilin, it is effective only at the caterpillar stage of development. Since Bt is a stomach poison, caterpillar mortality can not be expected until several days to two weeks after application. Approximately 70 percent of the gypsy moth caterpillar population will be killed with a single Bt application. This biological insecticide is harmless to useful insects as well as to humans and animals.

“Bt is more expensive to produce and apply than Dimilin but it’s more generally accepted by the public,” Mr. Wood said. “More is known about it.”

But Mr. McCarthy pointed out that the state will not share in the cost of a Bt spray program if the moth infestation is severe.

As to when and what to spray, Mr. Wood repeated that without a count of at least 500 egg masses per acre, “you’re not accomplishing anything by spraying. He also advised that “spraying uninhabited timber land is not generally viable from an economic standpoint... If you spray once, you’re making a decision to spray every two to three years indefinitely to save that timber.” There are other damage control measures, including early harvest, that are more feasible, Mr. Wood added.

Integrated pest management

“Insecticide spraying is the only known effective way to quickly suppress the gypsy moth population to tolerable levels,” the forestry consultant acknowledged. But if spraying is undertaken, “it should be part of a program of integrated pest management” that includes the introduction and protection of parasites and predators, Mr. Wood added. Predators and parasites won’t keep the gypsy moth population from irrupting the first time; “They won’t increase in numbers until there are gypsy moths for them to eat.” But they will check subsequent outbreaks,he said.

Asked about the possibility of introducing sterile male moths, a successful strategy against the Mediterranian fruit fly and the screw worm, Mrs. Thornhill reported that experiments with this approach are underway now in test plots. “They are doing it, but it’s going to take time.”

“Is there anything an individual can do now to protect what he’s I got?” asked Col. Deiter Knuepfer.

“Rub off the egg masses?” Super- ' visor Gilkey asked.

“Where the population is high enough to damage trees, finding and destroying egg masses is not an effective control,” Mr. Wood replied, reasserting that spraying is the only supressant that works.

“Are we going to spray? With what and under what conditions? Those are the questions we have to answer in our recommendation to the Board of Supervisors . . . We need a plan before the crisis is here,” Mr. Wood repeated.

In developing that plan, the committee is soliciting suggestions on:

• educational efforts.

• objectives. What should be the thrust of a control program? Protection of lawn and shade trees? Minimizing the impact on timber?

• how to monitor gypsy moth populations.

• whether to take part in a costshare spray program with the state.

• a statement of circumstances under which the county will provide financial or administrative support for an insecticide control program. Where are the critical areas for foliage protection? Where will the gypsy moth caterpillars have the greatest impact on people? Where are they likely to be intolerable?

Responses should be directed to members of the gypsy moth committee: Lyt Wood, Birgitt Thornhill, John McCarthy and Hubert Gilkey. Written comments and suggestions may be mailed to the Office of Building and Zoning, P. 0. Box 222, Washington, Va. 22747.