GREEN BAY, Wis. (WFRV) – As spring inches closer, so does a small caterpillar that has the potential to wreak havoc on local ecosystems—the European spongy moth, which was introduced to Massachusetts in 1869.
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Spongy moths have defoliated millions of acres of trees in forests and urban areas in at least 20 U.S. states. The spongy moth caterpillar can feed on more than 300 species of deciduous and evergreen trees, many of which are Wisconsin natives.
The spongy moth may have temporary, large increases, also listed as “outbreaks” in an area every 10-12 years, lasting 2-3 years.
Defoliation of susceptible trees may be widespread during these outbreaks; luckily, if the tree is healthy, it will likely survive a defoliation process as long as it is not a routine event.
The Wisconsin Department of Natural Resources (DNR) gives examples of management options such as egg mass oils, barrier and collection bands, physically destroying egg masses and drowning egg asses in soapy water. Click here to learn about insecticides from the DNR.
Spongy moths first appeared in Wisconsin in the late 1960s. Infestations were found in the Milwaukee area in the early 1990s, and have since been found in every county in the state, while the eastern two-thirds can be considered generally infested and are quarantined.
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The quarantine prohibits the movement of items that could harbor the spongy moth eggs, adults, or caterpillars to prevent them from moving to uninfested areas.
People living in non-quarantined counties may come across spongy moths. If you do, call 1 (800) 642-6684 or email spongymoth@wisconsin.gov.
Refer to the following link to learn how to identify a spongy moth caterpillar or look-alike species, Caterpillar Comparison (Common Spring Defoliators) fact sheet [PDF]. Click here for more from the DNR on the spongy moth.












