Gypsy Moth

MSU Extension-Livingston County is the county office that administers the Michigan Cooperative Gypsy Moth Suppression Program in the years that the county is enrolled.  This is a low cost, aerial spray program for areas with high gypsy moth populations.  The program is funded by U.S. Forest Service and is run through Michigan Department of Agriculture.  Counties enroll in the program and are able to provide a reduced cost to homeowners or municipalities for gypsy moth suppression. Individuals or municipalities cannot enroll, only counties.  The county must enroll by September of the previous year to be included in the May spray program. This is a voluntary program.  Property cannot be sprayed without the resident’s consent. 

The material used is Bacillus thuriengensis (Bt), a naturally occurring soil bacterium.  Suppression of gypsy moth is achieved by using only two quarts of Bt per acre.  The spray portion of the program is timed to when the larvae are small.  This usually occurs in mid to late May.  The spray is applied by fixed-wing aircraft.

Gypsy moth is an insect that feeds on over 300 kinds of trees and shrubs in the months of May and June. The larvae consume leaves of many trees, especially oaks. In severe outbreaks, trees can be completely defoliated. Check the links at the bottom of the page for more information to identify gypsy moth.

Livingston County has participated in this program in 1996-2000.  In the past several years, the gypsy moth population has been too low for the county to be enrolled.  For the county to participate in the Suppression Program there needs to be at least 500 acres with gypsy moth egg masses.  There must be 300 egg masses or more per acre to be considered a defoliation threat.

The Suppression Program has helped to control gypsy moth during years of high populations.  There are also two naturally occurring pathogens that help limit the gypsy moth population.  Entomophaga maimaiga, a fungal disease, and Nucleopolyhedrosis, a viral disease, control gypsy moth when there is weather favorable to these diseases activating. Those weather conditions would be rainy and warm in mid to late June.

In the years that the county is not enrolled in the Suppression Program, MSU Extension monitors for problems. If Livingston County residents have questions or concerns about gypsy moth, they can contact MSU Extension Livingston County for additional information.

	Gypsy Moth Identification Gallery
	The Michigan Department of Agriculture Gypsy Moth Web Page