Gypsy moths are tree pests that can defoliate large sections of forests and are among America's most destructive tree pests, having caused millions of dollars in damage. These moths are common in Wisconsin, but are now threatening Minnesota as well. Their preferred hosts are oak, poplar, birch and willow trees. The moths spread slowly on their own, but people can unintentionally speed up the process if they unwittingly transport firewood and other objects on which the moths have laid their eggs.
The Minnesota Department of Agriculture (MDA) has recently completed treatment of approximately 150,000 acres of land in Carlton and St. Louis Counties to slow the spread of the moth. The infestation was identified last summer and the MDA has been working hard to slow down the infestation before it takes hold.
The treatment used by the MDA is a method of aerial distribution of small flakes that are coated with a scent that is detectable only to gypsy moths. This scent mimics the natural pheromone female gypsy moths use to attract males. By applying the flakes with the “mimic” scent, the male moths are unable to find the female moths, and the mating cycle is disrupted. That means fewer caterpillars hatching and attacking new trees the following year. This form of treatment has been used in many other states and the results have shown a decrease in gypsy moth populations by more than 66 percent.
MDA works with the Minnesota Department of Health and other partners to develop treatment plans with minimal impact on human health and the environment. The product used in the Carlton County and St. Louis County treatment has no known health effects on humans or any animals aside from gypsy moths.
If there are any questions about the treatment to prevent gypsy moths, the MDA has set up an Arrest the Pest Hotline at 888-545-MOTH, giving details about treatment dates and times. Updates will also be made on the MDA’s Facebook page, their Twitter account, and the MDA's website.