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what's new in our current regional forest health updates.
how to identify and control invasive forest plants.
about gypsy moth and other spring leaf-eating caterpillars.
Contact information
DNR forest health staff

Suppression program pesticide information

There are a variety of insecticides that can help control gypsy moth populations (although none will completely get rid of the pest). Licensed pesticide applicators will consider several factors when choosing which product to use.

Aerial Spraying
Aerial spraying

The Wisconsin Gypsy Moth Suppression Program commonly uses the insecticide Foray® with the active ingredient BtK to spray for gypsy moths in the spring. Another product, called Gypchek, is used in areas where there are endangered moths or butterflies such as the Karner blue butterfly. These products are sprayed from a low-flying plane and are harmless to most people (although those with severe allergies or chemical sensitivities should try to avoid treatment areas when aerial spraying is happening). It is recommended that everyone in the spray area stay indoors during the spray to avoid direct exposure. The spray is sticky and smells a bit like stale beer.

There is plenty of information available about these pesticides. Below is a small sample.

View Aerial Pesticide Applications Fast Facts [PDF].

If you are considering hiring an aerial spray applicator, many helpful tips are available in the DNR’s Guide to Privately Organizing an Aerial Spray [PDF].

Bacillus thuringiensis (Bt) and Foray

Nucleopolyhedrosis Virus (NPV) and Gypchek

Pesticides used in ground sprays for yard trees

Last revised: Friday July 24 2015