Gypsy Moth Suppression Program

After fourteen years of operation, the DNR is proposing to deactivate the state gypsy moth suppression program. Communities, counties and individuals would need to directly contract with aerial applicators for aerial spraying of gypsy moth outbreaks, instead of having it done through the DNR. This means the following services would no longer continue:

  • Cost sharing from the federal government would no longer be available for the treatment or the associated administrative work.
  • Lists of county and municipal gypsy moth contacts for the public to use to report gypsy moth populations will be removed from and the DNR gypsy moth webpages.
  • The state would no longer track gypsy moth reports that come into the DNR call center from the public. Therefore, the state would no longer send logs of those reports to county and municipal gypsy moth contacts.

Why is DNR proposing deactivating the suppression program?

  • Increased numbers of for-hire aerial applicators that can do this work in Wisconsin
  • Decreased interest in this service in recent years
  • Uncertainty of future cost sharing from the federal government as federal funding is shifted to emerald ash borer, other invasive pests and firefighting costs

Would the state suppression program be reactivated in the future?

Communities, counties and individuals should make arrangements for private aerial sprays without the expectation of re-activation of a state program. Reactivation of the program is unlikely short of a catastrophic situation.


What assistance will the state provide for dealing with gypsy moth outbreaks?

Forest health and urban forestry specialists will continue to provide communities and landowners with guidance in managing gypsy moth just as we do for other urban and rural forest pests. The Wisconsin Cooperative Gypsy Moth webpage: has directions for assessing a gypsy moth population, options for control, and guidance on setting up an aerial spray project if an area is threatened with defoliation. Local governments and property owner associations in Wisconsin have used this guidance to conduct successful aerial sprays to prevent damage to their trees from gypsy moth and forest tent caterpillar.

If counties or communities wish to set up their own gypsy moth suppression programs to serve the needs of communities or individuals in the county, DNR staff can advise them on how to run such a program based on our experience. Federal cost sharing for gypsy moth suppression, however, would not be available. Counties in Michigan have handled gypsy moth outbreaks this way for nearly ten years and it has not reduced spray access in these counties.

The Forest Health Team has developed a variety of materials to help communities deal with outbreaks of gypsy moth, with or without a state suppression program. As mentioned, these materials are available online at: When creating these materials, we may not have thought of all of the services that are useful to you and part of the current state suppression program. We would appreciate your suggestions of information or guidance you would find helpful in running a private spray program. Your input will help us better understand your needs so we can provide better guidance when the state gypsy moth suppression program is deactivated. Some examples we have already considered are:

  • Directions on setting up email list serves so subscribers can get updates of spraying planned for the next day. This is one fast and easy way the state currently keeps the public informed during the spray program.
  • Frequently updated results of a model of gypsy moth development that the state uses to time sprays during May and June when spray treatments are done.
  • Links to health studies on Btk insecticides to provide to objectors.
  • Links to lists of for-hire applicators that can be contacted to make spray arrangements.