How To Help Defend Wisconsin Against The Spotted Lanternfly

WISCONSIN — As Wisconsinites clean up their yards headed into spring, they may want to keep an eye out for signs of spotted lanternfly, the destructive plant hopper that Agriculture Department officials say poses a serious threat to the nation’s grape, orchard and logging industries.

Wisconsin has not reported an established population of spotted lanternflies, but there have been some close calls reported. On Nov. 3, 2022, a Walworth County landowner reported finding multiple dead and one "dying" adult spotted lanternflies on stock bought from a nursery in Illinois, according to the Wisconsin Department of Agriculture, Trade and Consumer Protection.

"This serves as a reminder to always inspect your stock upon arrival in the nursery trade and prior to planting in your yard," the department said in a release at the time.

Established spotted lanternfly populations were recorded last year in 14 states including Connecticut, Delaware, Indiana, Maryland, Massachusetts, Michigan, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, Virginia and West Virginia.

Last year, ag officials said spotted lanternflies were moving westward into the central United States, with new reports filed in Iowa, Michigan and North Carolina. Reports were also filed in Kansas in 2021. States farther west, including Utah, California and Oregon, have also observed dead lanternflies, though it’s unclear if the plant hoppers naturally migrated there, or hitched a ride with humans.

When the spotted lanternfly arrives in Wisconsin, it will likely be found on the tree-of-heaven or Ailanthus altissima, although it can also be found on several other species throughout the growing season, according to a report by the Wisconsin First Detector Network, a program under the University of Wisconsin-Madison that seeks to act against invasive species.

Most states are at risk because spotted lanternfly populations move around easily, according to the USDA. They prefer to lay their mud-like egg masses, which can contain as many as 50 eggs, on the trees they feed on plus surfaces on movable objects like bicycles, lawnmowers, grills and the family car.

Removing and destroying egg masses now before hungry nymphs emerge is the best defense against their spread, ag officials say. The insects are at their most destructive at that point, feeding on more than 100 varieties of fruit, ornamental and woody trees, as well as vines, vegetables, herbs and grains. Areas with substantial grape industries are worried because a spotted lanternfly infestation can not only reduce yield, but lower the sugar in remaining grapes.

Nymphs also feed on hops, which is emerging as a high-value crop in Wisconsin alongside grapes, the Wisconsin DATCP noted in a fact sheet. Roses and other ornamental crops plus hardwoods that are important to the state's logging and paper industries could also be at risk, the DATCP said.

Here’s what to look for:

By now, egg masses will have faded from glossy white to gray or brown, and they’re about an inch and a half long. If you find an egg mass:

Take a picture and report it to the state Department of Agricultural, Trade and Consumer Protection. Scrape off egg masses, put them in a plastic zippered bag filled with hand sanitizer, then zip the bag and dispose of it in the garbage.

In a widespread population control effort, people in areas with infestations were encouraged to squish adult lantern flies — before they deposited their egg masses — wherever they encountered them.

You can find out more about how to fight spotted lanternflies in Wisconsin through the DATCP website.