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Gypsy moth suppression program

The Wisconsin Department of Natural Resources Gypsy Moth Suppression Program:

  • works to suppress damaging gypsy moth populations with an aerial insecticide treatment;
  • only works in eligible and participating counties, where the county has requested treatment, has a county coordinator and has agreed to participate and follow program requirements;
  • is run by the state, in partnership with counties, municipalities and landowners who voluntarily request treatment by applying to the program through their county coordinator;
  • mainly serves the eastern part of Wisconsin in gypsy moth quarantined counties; and
  • offers an opportunity for communities and property owners to manage damaging gypsy moth populations (outbreaks) with more confidence than is possible with most privately arranged aerial treatments.

Gypsy moth suppression plane Gypsy moth suppression plane

In the western part of Wisconsin where small, isolated populations of this pest are just starting to show up in non-quarantined counties, another program called Slow The Spread (STS) [exit DNR] is run by the Department of Agriculture, Trade and Consumer Protection (DATCP). The STS program is not voluntary and DATCP does not take landowner or municipal requests for sprays.

How the county partnerships work

County officials coordinate the suppression spray program with assistance from the DNR. Participating counties provide a local coordinator who acts as a contact for the public and the DNR. This coordinator is responsible for duties that are best performed or can only be performed at the local level.

For example, coordinators usually collect payments for the full cost of spraying from communities and landowners. The DNR will apply for a federal cost-share grant that is available only to states. If cost sharing is available, the state reimburses participating counties up to 50 percent of the cost of treatment and administrative expenses. The county coordinator then distributes the federal cost-sharing reimbursements to communities and landowners who originally paid.

How to request an aerial suppression program treatment on your property

If you are having a problem with gypsy moth on your property (in a gypsy moth quarantined county of Wisconsin) and would like to apply for the DNR's suppression spray program, contact your county and municipal coordinators for the spray program. These people help in the process of suppressing gypsy moth populations in your area.

Not all counties participate in this program. In that case, the county will not have a coordinator and properties in that county will not be sprayed. If your county is not currently participating in the program, you may contact your county government officials and the local community government to report the problem and express interest in participating if your neighborhood is heavily infested.

Adult female moths depositing egg masses
Adult female moths depositing egg masses

Tell your county and municipal contacts that you want your property sprayed as soon as you know

The suppression program sprays in May and June. Areas proposed for spray treatment are determined in September, October and November of the previous year, based on gypsy moth population numbers and other requirements. Let your government officials, county coordinators and local contacts know about your interest in participating in the suppression spray program as early as possible (as soon as you notice a large population of gypsy moth caterpillars, moths or egg masses on your property).

What to do if your county is not and will not participate in the suppression program

You can look into other options for treating your property if your county is not currently participating in this program. Ground based sprays can treat a few yard trees and are usually done by a certified arborist [exit DNR]. If you have more than 20 acres, you can also organize a private aerial spray project.

Suppression program insecticides

Insecticides used in the DNR suppression spray program are either Foray, a formulation of the bacterial insecticide Bacillus thuringiensis kurstakii (Btk) or Gypchek, a viral insecticide specific to gypsy moth caterpillars. Gypchek is only used where endangered or threatened moths or butterflies are present. Both Btk and Gypchek are unlikely to cause any adverse health reactions.

Small airplanes will spray Btk and Gypchek in late May and early June, beginning very early in the morning. Homeowners in areas to be sprayed are encouraged to stay indoors with windows closed in order to avoid direct exposure to the spray. It is sticky and smells a bit like stale beer.

The suppression program is managed under State Statute 26.30 and Natural Resources Board Rule number 47.

Last revised: Wednesday December 20 2017