Residents of 16 western Wisconsin counties can expect to see and hear loud, low-flying planes as early as sunrise starting in early-mid May.

Small, yellow planes will be treating for invasive gypsy moth caterpillars. These non-native pests defoliate many kinds of trees and plants during their caterpillar stage, causing stress and potentially tree death. Treatment efforts are focused in western Wisconsin where gypsy moth populations are low or beginning to build, in an attempt to slow their spread.

The harmful effects of gypsy moths include the cost of removing dead trees and potential los...