(FOX 2) - Michigan's first case of elm zigzag sawfly has been detected in St. Clair County following a confirmed report through the region's invasive species network.
The pest feeds on elm trees and can be a problem for the tree species' foliage, the Michigan Department of Agriculture and Rural Development said in a news release.
However, the MDARD director said elm trees can typically recover from the damage suffered by the zigzag sawfly.
Big picture view:
Detection of the elm zigzag sawfly came following a report that was submitted by an arborist through the Midwest Invasive Species Information Network.
The Animal and Plant Inspection Service under the U.S. Department of Agriculture confirmed the detection.
There's a reason the invasive pest is called the zigzag sawfly, getting its name from the young larvae that create a "zigzag" pattern when they feed on the edges of leafs growing on elm trees.
The older larvae eat most of the trees, creating large notches in the foliage. Director Tim Boring said the pest's emergence does not pose a significant threat to the state or its natural resources.
"The elm trees this invasive pest feeds on can typically recover from defoliation by producing new foliage. We encourage residents to be aware of this pest and report suspected sightings to help track its distribution in Michigan."
Where did it come from?
The zigzag sawfly is native to Asia before first being found in Canada in 2020.
It was first spotted in the U.S. in Virginia in 2021. Because the adults can fly easily and reproduce rapidly, the sawfly has easily spread through several states in the east and Midwest.
If someone does find the fly, it will likely be in its larval stage, according to an MDARD press release announcing the discovery. At that stage, the insect takes the shape of a yellow-green colored caterpillar-like larvae.
The larvae measure 10-11 mm long and have a brown band on their head and dark T-shaped markings on the hind legs.
The sawflies take the shape of 7-8 mm-long insects with shiny black bodies, smoky wings, and pale yellow and whitish legs.
The Source: A Michigan Department of Agriculture and Rural Development press release was cited for this story.