Gypsy Moth

Pheromone Flakes

Pheromone (fair-uh-mone) flakes are about the size of a grain of rice. They also are flat and green, and carry the scent of the female gypsy moth. Pheromone flakes are used to confuse male moths as they search for a mate.

The sticky flakes are applied at a rate of one to two flakes per square foot of tree canopy. At this low application rate, it is unlikely that people will see the flakes.

When will pheromone flakes spraying begin?

We usually begin spraying pheromone flakes in southern Wisconsin in June or early July and move northward, finishing in early August. Planes may start spraying as early as 6 a.m., weather permitting, and may continue into the evening.

Why must planes spray in the morning?

We need low winds to assure that the flakes land on the tree leaves.

Are the flakes harmful to humans?

Pheromone flakes are not harmful to humans. The flakes carry and release the pheromone of the female gypsy moth that is only detectable by male gypsy moths.

Are the flakes harmful to animals?

The flakes will not harm animals, but the low-flying planes may frighten pets or livestock. It is recommended to keep animals inside, if possible. If that is not possible, keep a close watch on them.

Are the flakes harmful to car finishes?

No, but if you do find any flakes stuck on your vehicle, you may need to pre-treat any spots or use some elbow grease while washing.

Fast Fact sheet about pheromone flakes- 1 page PDF (You will need a PDF reader to view this document.)

For more information, call toll free 1-800-642-6684 and select option 3, or e-mail gypsymoth@wisconsin.gov.