New Threat to Michigan Trees

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The Michigan Department of Agriculture says yet another potentially devastating insect is infesting some of the state's trees.

The hemlock woolly adelgid has been attacking hemlock trees, which are popular landscape evergreens and an important component of hardwood forests in northern Michigan.

A landscaper recently alerted officials about white, cottony masses on hemlocks that had been planted in 2003 at four sites in Harbor Springs. The trees came from the same nursery in West Virginia. It marks the first time the insect has been discovered on Michigan's native hemlock trees, the Detroit Free Press reported Wednesday.

The hemlock woolly adelgid is among the most serious exotic forest insect pests to have entered Michigan, Deborah McCullough, a forest entomologist at Michigan State University, told the newspaper.

Their arrival comes on the heels of the emerald ash borer, which is blamed for the loss of nearly 20 million trees in Indiana, Ohio, Michigan and neighboring Ontario since it first was found near Detroit in 2002.

Experts from the state agriculture and natural resources departments and from Michigan State are working on a plan to eliminate the hemlock woolly adelgid, which could cause some trees to be destroyed while others will be treated with insecticide.

Agriculture officials also are trying to track where 1,900 hemlocks imported to northern Michigan from out-of-state growers are located and whether the trees are healthy.

The insect is transported by wind, people and animals.