New invasive insect found in Minnesota

A new invasive insect has been spotted for the first time in Minnesota. The Minnesota Department of Agriculture (MDA) says they learned about the elm zigzag sawfly when a individual reported it to iNaturalist, a website where people can share observations with other naturalists and scientists.

Minnesota state officials were notified of the discovery and MDA says scientists collected larvae and the identification was confirmed by the Smithsonian Institute Museum of Natural History.

The elm zigzag sawfly is native to East Asia. MDA says the invasive insect feeds on the leaves of elm trees. The young larvae create a distinctive zigzag pattern through the elm leaves while feeding. The larvae are green with a black band on their head and they have T-shaped brown or black markings on the top of their second and third pair of legs.

First confirmed in the United States in 2021, the elm zigzag sawfly has been found in several eastern states and now Minnesota.

MDA says the potential impacts of the elm zigzag sawfly are unknown because the invasive species has not been in the United States very long. It does cause defoliation of elm trees, but officials say most trees can recover.

With this new finding, MDA would like to better understand where this insect may be in the state. Residents can report suspected sightings of the insect to the MDA’s Report a Pest line or call 1-888-545-6684. Please include clear photos when submitting a report online.

More information on the elm zigzag sawfly is available on the North Carolina State website.