Gypsy moth spraying begins

May 21, 2001

Gypsy moth spraying begins


They don't look intimidating but the small, furry gypsy moth caterpillar can be a farmer or homeowner's worst nightmare.

The insects have voracious and indiscriminate appetites for leaves and can damage a tree in a short period, said Mark Taylor, program coordinator of the Maryland Department of Agriculture gypsy moth survey and control program.

Taylor said that this year, workers are spraying 48,543 acres across the state to stop the tiny terrors. In Washington County nearly 8,000 acres were selected for spraying after a survey of egg masses was conducted in August.

"This year's the worst it's been in many years," he said of the infestation.

In Pennsylvania and West Virginia, pest management officials are telling the same story.

More than 8,000 acres in each of Franklin and Fulton counties in Pennsylvania were sprayed for the insects. In West Virginia, 2,770 acres in Jefferson, 4,513 acres in Berkeley and 18,462 acres in Morgan counties have been or will be sprayed this week, pest management officials said.


Workers use helicopters to drop insecticides on trees in designated areas and the caterpillars die after eating a quantity of the sprayed leaves, said Taylor.

Taylor said they use two different types of insecticides, Bacillus thuringiensis or BT, which is a natural agent found in mud and compost and Dimilin, a chemical which prevents young gypsy moths from developing.

"It's like the fountain of youth for gypsy moths. They never grow old," said Taylor of Dimilin.

Both are non-toxic to people and pets and wash off cars and clothes, he said.

Dimilin is more effective but its use is restricted over bodies of water, he said.

The gypsy moth population in the state is cyclical over several years, according to Taylor. Once populations grow out of control and food becomes unavailable, they die off. It's the same with other pests.

"It's Mother Nature's way with rats, roaches and gypsy moths," he said.

J.D. Hacker of the West Virginia Division of Forestry said the caterpillar's numbers depend heavily on the presence of a gypsy moth fungus.

The fungus, which kills off the insects, thrives in wet weather. This spring has been mostly dry throughout the Tri-State area, allowing the caterpillar population to go unchecked, he said.

Gypsy moths are troublesome because, though they prefer oak trees, they will eat just about any type of leaf, said Taylor.

"When they're are hungry they don't care," he said.

The insects also breed prolifically, he said. A female can lay an egg sack with 1,000 eggs. Potentially, 500 of them can be female.

Gypsy moths hatch in mid-to-late April or early May, depending on location, and begin eating young leaves. They've been known to eat over 400 different varieties of trees and plants.

Trees can tolerate losing their leaves to pests once in a while. But trees defoliated for three consecutive years usually die, according to officials.

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