April showers not only bring May flowers, but they also can reduce the outbreak of gypsy moths. The winged invaders are on the upswing, and unless there's a wet spring to help spread a naturally occurring virus that attacks the moths at the caterpillar stage, state officials expect to spray about four times as much land with pesticide than they did just two years ago.

Gov. Martin O'Malley has asked the legislature to approve $3.5 million so the Maryland Department of Agriculture can treat 100,000 acres of hardwood forest this spring through aerial spraying, chiefly from Garrett to Cecil counties. The agency uses two pesticides, the bacillus thuringiensis, or Bt, and the more controversial diflubenzuron, also known as Dimilin, which is toxic to certain aquatic life and other insects.

Gypsy moths pose a serious threat to Maryland forests. Officials estimate this summer could bring the largest infestation since 1994, a remarkable increase considering the state had so few moths in 2005 that aerial spraying was temporarily abandoned. But it's also reasonable to be concerned about the effects of Dimilin on the environment. And while it's not considered highly toxic to humans, the pesticide is not risk-free, either.

The state Senate has approved legislation creating a task force to study the growing gypsy moth problem and the best way to combat the infestation. The House should follow suit. Gypsy moths can ravage the landscape, but we need to ensure the techniques used to eradicate them aren't a threat as well.