New Invasive Insect Threatens Elm Trees In Minnesota: What You Need To Know

WHY WHY WHY

More bad news for the Elm tree. An invasive insect that feeds on elm tree leaves and creates a unique zigzag pattern on the leaves while it eats them, has been found here in Minnesota.

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

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MEET THE ELM ZIGZAG SAWFLY

The Elm Zigzag Sawfly is native to East Asia and was first found in the United States back in 2021. The Elm Zigzag Sawfly was recently reported on the University of Minnesota Twin Cities campus. Larvae were collected and the Smithsonian Institute Museum of Natural History has confirmed that it is indeed the Zigzag Sawfly.

What kind of impact will this insect have on our elm trees? The agriculture department released this statement in a news release:

"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."

WHAT SHOULD YOU DO?

Research is underway, but since most trees can recover, they say that management of the insect may NOT be necessary, but it looks like it is too soon to tell at this time.

If you find that your elm trees have been affected by this insect, it is important that you contact the agriculture department on the Report A Pest line, or call 1.888.545.6684.