Species of concern

  • asian longhorn beetle Asian Longhorned Beetle

    (Anoplophora glabripennis)

    Watch List - Prohibited in Michigan

    The Asian longhorned beetle can attack and kill many tree species including poplar, willow, sycamore, and horse chestnut, but its favorite host are maple trees. The larvae feed in tunnels in the wood of the tree branches and trunks, eventually killing the tree.

  • beech bark disease thumbnail Beech Bark Disease

    (Cryptococcus fagisuga + Neonectria spp.)

    Beech bark disease (BBD) is caused by both a sap-feeding scale insect and a fungus. American beech trees are first infested with beech scale. Scale feeding allows infection by the Neonectria fungus. The fungus kills the wood by blocking the flow of sap. Some infected trees break off in heavy winds before dying. The scales are covered with white wool, turning infested portions of the tree white.

  • Emerald Ash Borer Emerald Ash Borer

    (Agrilus planipennis)

    Prohibited in Michigan

    The Emerald Ash Borer is a bright, metallic green insect with purple abdominal segments under its wing covers. They are approximately 1/2 inch in length and can fit on the head of a penny. The larva are worm-like. The adults feed on the foliage of ash tress and the larvae tunnel and feed on the underside of the bark.

  • Hemlock woolly adelgid Hemlock Woolly Adelgid

    (Adelges tsugae)

    Watch List

    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.

  • Oak Wilt Thumbnail Oak Wilt

    (Bretziella fagacearum)

    Oak wilt kills healthy red oaks. White oaks can also be affected but are more resistant and less vulnerable to mortality from the disease. Look for red oaks that suddenly drop their leaves in the summer. The disease spreads, killing nearby oaks from one year to the next.

  • A spotted lanternfly with its wings open Spotted Lanternfly

    (Lycorma delicatula)

    Watch List

    The spotted lanternfly sucks sap from the stems and leaves of orchard trees, grape vines, oaks, pines and other host plants. Feeding can weaken the plant and evenually contribute to its death. Trees will develop weeping wounds that attrach other insects and excreted fluids from spotted lanterflies can cause mold growth on plants.  

  • Thousand Cankers Disease Thousand Cankers Disease

    (Pityophthorus juglandis + Geosmithia morbida)

    Watch List

    Thousand Cankers Disease involves an insect native to the southwestern U.S. The disease affects black walnut trees, a valuable economic and ecological resource in Michigan.

  • Sign up for Forest Health Email Alerts