Hemlock Woolly Adelgid

Hemlock woolly adelgid

(Adelges tsugae)
*Detected in Michigan*

Report this species:

If you notice white, waxy material at the base of the needles on hemlock trees, to prevent spread, do not remove potentially infested material from the site. Take photos, note the location of the affected trees and report it to:

Michigan Department of Agriculture and Rural Development, MDA-Info@michigan.gov or phone the MDARD Customer Service Center, Call: 800-292-3939.

- Or - use the Midwest Invasive Species Information Network (MISIN) online reporting tool

- Or - download the MISIN smartphone app and report from your phone

Hemlock woolly adelgid
Elizabeth Willhite, USDA Forest Service, Bugwood.org

hemlock woolly aledgid
CAES, Bugwood.org - Hemlock woolly adelgid up-close 

Hemlock Woolly Adelgid damage
Mark McClure, Connecticut Agricultural Experiment Station - Hemlock woolly adelgid damage


Why we care: These tiny insects secrete white wax as they feed on sap from hemlock shoots and branches. Hemlock woolly adelgid (HWA) feeding can kill needles, shoots and branches. Over time, growth slows as trees become less vigorous and trees may take on a grayish-green appearance. Infested hemlocks, especially large, old trees, are often killed when other stress factors, such as drought, affect trees.

What is at risk? More than 100 million mature hemlocks grow in Michigan. Hemlocks provide important habitat and winter cover for many wildlife species.

The threat: HWA populations are common in many eastern states, including Pennsylvania. Eggs and very young adelgids can be carried by birds and can be moved on hemlock nursery trees, logs or firewood.

What could happen in Michigan? Much of the state's hemlock resource is relatively old and very vulnerable to HWA. If this pest becomes established, most of these trees will be killed.



Allegan, Muskegon, Oceana, and Ottawa Counties Hemlock Woolly Adelgid Information:

Educational Materials:

What does Hemlock and Hemlock Woolly Adelgid Look Like?   

Quarantine Information 

Links of Interest