Mitigating effects of invasive insect attacking hemlock trees

A tiny insect — no larger than 1.5 millimeters in length — threatens more than 170 million trees in Michigan, and the cascading ecosystem effects could be catastrophic.

October 1, 2018

Deb McCullough

A tiny insect — no larger than 1.5 millimeters in length — threatens more than 170 million trees in Michigan, and the cascading ecosystem effects could be catastrophic. Michigan has already experienced this with previous invasive pests, but this latest one — hemlock woolly adelgid — threatens not only trees but also the health of aquatic species and wildlife as well. The HWA preys on hemlock trees, which are vitally important to the ecological health of aquatic species and wildlife throughout Michigan. Hemlocks provide dense shade during periods of extreme weather that helps to protect animals. They typically grow along the banks of lakes and rivers, where they help to provide nutrients to soils and waterways.

  • The adelgid may have been in Michigan for about 15 years, but if so, the populations stayed low and went unnoticed. Small, localized infestations near the Lake Michigan shoreline were discovered in 2015, and additional adelgid hot spots have since been found in four western Michigan counties.
  • MSU researchers are working to develop a statewide hazard map that will identify where hemlock is abundant and the pest is most likely to thrive. Those areas can then be prioritized for HWA surveys and mitigation efforts to reduce impacts of the pest.

Tags: natural resources

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