April 10, 2023
Trapping data collected by the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) indicates that the spongy moth (formerly Gypsy Moth), an invasive insect from Europe that feeds on the leaves of more than 300 tree species, is now established in Douglas County.  As a result, this county has been placed under state and federal spongy moth quarantine, joining most of eastern and central Wisconsin already considered to be infested with the pest.

This is the first time since 2021 that a new county has been added to the quarantine, and 53 of Wisconsin’s 72 counties are now quarantined for spongy moth. The quarantine has the greatest impact on plant nurseries, Christmas tree growers, loggers and sawmills because of movement restrictions and inspection requirements. These types of businesses must enter into a compliance agreement with state or federal plant regulatory officials certifying that their nursery stock and wood products are free of spongy moth before they can be transported into non-quarantined counties or states.

 

People living in a quarantine county must be careful when moving outdoor items. Because spongy moths can lay egg masses on nearly anything kept outside, and a single egg mass can contain up to a thousand eggs, there is a risk of spreading spongy moth when transporting items like patio furniture, campers, boat trailers or firewood.

“If you are going camping or heading to your cabin, check your gear before leaving to be sure you aren’t carrying spongy moth egg masses or caterpillars with you,” said Brian Kuhn, director of the Plant Industry Bureau at DATCP. “This is very important if you’re headed to areas in far western Wisconsin, Minnesota or Iowa where the spongy moth population is low. A county can be infested without showing immediate damage and it is on all of us to practice diligence to keep this invasive pest from damaging more of our plants.”

 

It is important to remember the quarantine restrictions even though you may not notice widespread tree damage in the quarantine area. Spongy moth is an invasive pest that has been spreading westward since its introduction to North America. Spongy moth caterpillars feed on the leaves of many species of trees and shrubs, especially oaks, and can cause severe leaf loss when feeding in large numbers.

 

For more information, contact
Plant Protection Section Manager Shahla Werner at (608) 957-5100 or shahla.werner@wisconsin.gov.
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