INVASIVE SPECIES. BAD FOR TREES.

Invasive species are plants or animals that are normally not found in a place and are so aggressive or numerous that they can crowd out or kill the plants or animals that naturally live there. Some invasive species – both fungi and insects – destroy our trees. The Michigan Department of Natural Resources works hard to stop the spread of these invasive species to save our trees.

BEECH BARK DISEASE

– What Is It?
An insect that attacks the bark of beech trees. The scale insect is yellow, elliptical shaped and can be seen in large numbers on tree trunks where it feeds on the liquids of bark cells.
– When Did We First See It?
It is believed the scale insect was accidentally brought to Nova Scotia around 1890. By 1932, the scale and fungus were killing mature beech trees in the northeastern USA
– What Are the Signs?
The scale appear as white woolly spots. Heavy infestations turn the trunk white. As trees weaken. the trunks often break just below the tree crown. Beech Bark Disease is spread by birds squirrels and other animals moving from an infected tree to healthy trees as well as by people moving infected firewood
– What Happens?
The scale sucks sap from the tree. Both the feeding wounds and stress caused by reeding predisposes the tree to li fection by the Nectria fungus. It is the fungus that ultimately kills the tree.
There is no way to control the disease. Once infested with scale, tree trunks often break, and can become a hazard to people and property. In forested areas, scale infested beech are harvested before they snap and lose value as wood products.

OAK WILT

– What Is It? Oak wilt is a fungus that kills oak trees. All species of oak trees can get the disease but red oak trees get it most often. – When Did We First See It? First noticed in 1944 in Wisconsin, and has been found in 21 states with the worst damage being in the Midwest – What Are the Signs? Leaves that turn dull green or bronze, look water-soaked, wilt, and then turn yellow or brown and fall from the tree in mid-summer. Leaves are often green on one end and brown on the other with a distinct line between the two areas. – What Happens? Once infected, trees can die within days or weeks. There is no way to save an infected tree. lo stop the underground spread of disease, root graits between sick and healthy trees are cut using a vibratory plow. Then the diseased trees are cut down and properly disposed of to prevent overland transmission of spores to wounds on healthy trees by picnic beetles.