On November 12, 2010, the Michigan Department of Agriculture confirmed the findings of Hemlock Woolly Adelgid in Emmet, Macomb, and Ottawa counties. Native to Asia, the Hemlock Woolly Adelgid are an invasive insect species that feed exclusively on coniferous trees. The insects damage the trees by sucking sap from the twigs at the base of the needles which eventually causes the tree to lose its strength and the needles to fall off. Unlike insects that feed off the nutrients of sap, the Hemlock Woolly Adelgid feeds on stored starches. These starch reserves are critical to the tree's growth and long-term survival. If the Hemlock Woolly Adelgid go unmonitored, they can kill an entire tree within one or more years.
The positive sites in Macomb and Ottawa Counties were reported by two arborists and the one in Emmet County was discovered by an inspector with the MDA. This reinforces the importance of citizen involvement in the discovery and reporting of exotic pest infestations. Early detection will allow the infestation to be treated and eradicated. Homeowners are being asked to check any hemlock growing on their property looking for cottony white masses at the base of the needles and report any findings to the MDA. Infested trees will be removed and destroyed. Any new hemlock should never originate from infested areas and should have proper certification.
Hemlock Woolly Adelgid was first discovered in 1951 in Virginia and has spread over an area from Georgia to Maine. The insect has decimated hemlock in the Eastern United States. The Hemlock Woolly Adelgid was first discovered in Michigan in 2006 in hemlock trees planted in Harbor Springs for residential landscaping. The trees, from an infested nursery in West Virginia, were removed and the area was treated and surveyed for several years after. It is believed that the current infestation also originated from hemlock nurseries in infested area of the United States.
Hemlock trees play an important role in the ecology of Michigan's forests, providing habitats for many animals including deer, birds and fish. There are over 100 million trees in Michigan's forests. Michigan law bans moving hemlock to the state from infested areas. Details on the hemlock quarantine and additional information on the Hemlock Woolly Adelgid can be found at www.michigan.gov/mda.