Elm zigzag sawfly, an invasive insect, found in Minnesota for the first time

MINNEAPOLIS — Minnesota agriculture officials announced Tuesday the discovery of an invasive insect new to the state.

According to the Minnesota Department of Agriculture, the elm zigzag sawfly was recently reported on the Univerity of Minnesota Twin Cities campus. After being notified of the discovery, state officials collected larvae and the Smithsonian Institute Museum of Natural History confirmed it as an elm zigzag sawfly.

As its name implies, the invasive insect feeds on elm tree leaves, creating a distinctive zigzag pattern on the leaves while feeding.

Officials say the larvae are green with a black band on their heads. They also have T-shaped brown or black markings on the top of their second and third pair of legs.

The elm zigzag sawfly was first discovered in the United States in 2021. It's native to East Asia.

"The potential impacts of the elm zigzag sawfly are unknown because of the short period of time it has been present in the United States. Although the insect causes defoliation of elm trees, most defoliated trees can recover from a defoliation event," the agriculture department said in a news release.

Since most trees can recover, management may not be necessary, according to officials. Research is currently underway at North Carolina State on applications of insecticide.

Residents who suspect sightings of the insect are encouraged to report it on the agriculture department's Report a Pest line or call 1-888-545-6684.