Minnesota vs. Spongy moths - can traps save trees?

By Scout Nelson

The Minnesota Department of Agriculture (MDA) has launched a significant initiative to set about 20,000 traps across the state's eastern regions to monitor the spongy moth (Lymantria dispar). This operation is a key part of the MDA's ongoing efforts to protect Minnesota’s lush forests and vibrant urban landscapes from the potentially devastating impacts of this invasive species.

Spongy moth caterpillars pose a significant threat due to their appetite for the leaves of over 300 types of trees and shrubs, with a particular preference for oak, poplar, birch, and willow. These infestations not only damage vegetation but also become a nuisance to humans.

The trapping survey, conducted annually, plays a crucial role in the early detection of spongy moth populations and helps slow their spread through targeted management practices.

“With the public’s help, this work protects industries like tourism and forestry from economic harm and saves Minnesota’s urban and forested areas from environmental damage,” remarked Mark Abrahamson, Plant Protection Director.

This year’s trapping will be conducted by nearly 40 MDA staff members from May through July, with traps remaining in place until mid-September in southern areas and through October in northern regions.

The traps, designed as small, triangle-shaped "delta" traps and larger "milk carton" shaped traps in high-risk zones, are equipped with pheromones to attract male moths.

Citizens are encouraged to respect the trapping grid by not disturbing the traps. They can report any concerns or request relocations by calling the MDA’s Report a Pest line at 888-545-MOTH (6684) or email spongy.moth@state.mn.us.

The public is urged to report any sightings of the spongy moth through the MDA’s online service, enhancing the effectiveness of the state’s monitoring and response strategies. This collective vigilance is important for maintaining the health of Minnesota’s natural and developed environments.

Photo Credit - gettyimages-ian-redding