The Department of Natural Resources says planes will begin gypsy moth spraying in western Wisconsin this week. The effort will last for several weeks. The planes will be overhead in Barron, Chippewa, Crawford, Douglas, Dunn, Grant, Green, Iowa, La Crosse, Lafayette, Rusk, Trempealeau, Vernon, and Washburn counties. Gypsy moths eat the leaves off of trees and plants during their caterpillar stage. That stresses the trees and can even kill them. State officials say the gypsy moth is a threat to Wisconsin’s forests and a “periodic public nuisance.” People living in those 14 counties will see the small, yellow planes flying overhead from time to time this month.