The gypsy moth is a small insect causing a big problem.
The inconspicuous gray moth, an invasive species from the Eastern Hemisphere, is treating the nation's forests like an all-you-can-eat salad bar, defoliating millions of acres of forests each year, said John Kyhl, regional gypsy moth suppression coordinator and forest entomologist for the Wisconsin Department of Natural Resources.
Wisconsin is no exception. Last year gypsy moths defoliated an estimated 45,000 acres, Kyhl said, almost double the acreage lost in 2002.
The speed with which the moth has spread and the sheer magnitude of its appetite may have caught Wisconsin officials by surprise in the past, but now they are fighting back.
Come spring, an estimated 30,000 acres in eight southeastern Wisconsin counties will be sprayed to discourage Gypsy moths, Kyhl said. Milwaukee County has approximately 8,724 acres slated to be sprayed.
Statewide, over 51,000 acres in 20 counties will receive the anti-moth measure. The USDA is also operating a program in the western two-thirds of the state called "Slow the Spread" that will involve 300,000 to 325,000 acres in preventing the spread of the gypsy moth.
All 49 communities that expect to be sprayed have requested the service, Kyhl said.
To kill the gypsy moths, the DNR will spray a fine mist of the bacteria bacillus thuringiensis kurstaki, or BTK, from planes, Kyhl said. The bacteria will coat leaves and foliage and will be consumed by gypsy moth caterpillars, then go to work inside the acidic gut of the caterpillar and kill it without harming other organisms, Kyhl said.
"It has a low toxicity to things that aren't caterpillars," Kyhl said. "You could spray it on ladybugs or dragonflies and it would have no effect. You don't end up harming anything you didn't mean to harm."
The sprayings appear to be the most effective way to rid Wisconsin of the moths, which lack any natural predators, parasites or viruses to keep their population in check.
Though only recently used as a weapon in the anti-gypsy moth arsenal, BTK has been used in pest control for many years, according to biology professor Dale Noel.
"It's fairly common," Noel said. "It's done quite often in agriculture."
The gypsy moth travels by hitchhiking on people's belongings when they move from place to place, Kyhl said.
It is not known exactly when the gypsy moth first arrived in Wisconsin, but it has established a growing presence here and is causing untold damage.
gypsy moths reproduce extremely rapidly, Kyhl said. One gypsy moth female is capable of producing 600 eggs in her lifetime, most of which develop into caterpillars.
That's where the trouble begins.
"I can't even count how many calls I got (last summer) saying 'I have 1,000 caterpillars on the side of my house,'" Kyhl said.
The caterpillars satiate their voracious appetites by consuming the leaves of any of the 500 species of trees and shrubs they've been found to be able to digest, Kyhl said.
"They cause a lot of concern because of their great damage to trees," he said.
The damage done by gypsy moths extends far beyond defoliating trees, however. Unsightly clumps of gypsy moth eggs, sheets of writhing caterpillars and clouds of the moths themselves all deter visitors from Wisconsin's resorts and parks, putting a dent in Wisconsin's economy. Continuous plagues of gypsy moths drive down property values, and some people may even experience an allergic reaction to the moth's millions of fine hairs, Kyhl said.