About 19,000 gypsy moth traps are being set across Wisconsin to monitor the invasive insect.
Trappers from the state Department of Agriculture, Trade and Consumer Protection began setting the traps earlier this month and plan to have them all in place in 50 counties by early July.
The traps are used to measure where the moths are, not to control the population. Information gathered is used to help determine where to spray to kill moths next year.
The traps only catch male gypsy moths because they can fly and the females cannot. The traps will be in place until the male moths stop flying in August.
The gypsy moth in its caterpillar stage is known to feed on and defoliate more than 300 different species of trees and shrubs.