Caterpillar Species in Michigan

Michigan is home to a number of different caterpillars. They live throughout the state, and feed on numerous types of trees. Large outbreaks of certain types of caterpillars can lead to major defoliation of trees. While the beauty and leaves of a tree might be damaged for a year, Michigan caterpillars rarely cause permanent damage to the trees.

  1. Forest Tent Caterpillars

    • Forest tent caterpillars are common in Michigan. Widespread outbreaks of forest tent caterpillars in Michigan normally occur every 10 to 15 years according to the Michigan Department of Natural Resources. Broadleaved trees in the northeast are the most common types for this caterpillar to feed on, including sugar maple, willow and oak trees. These caterpillars can defoliate an extensive amount of wooded areas, but normally cause only minimal long-term damage. Newly hatched forest tent caterpillars are almost always black and will develop whitish spots on the back when they grow older. They reach a maximum length of 2 inches and will form a silken mat on the trunk of the tree.

    Gypsy Moth Larvae

    • Gypsy moths caterpillars or gypsy moth larvae have increased in numbers in Michigan. The gypsy moth was accidentally introduced to Massachusetts from Europe in the late 1800s, and found its way into Michigan in the 1950s. Gypsy moth larvae can cause defoliation of trees, particularly oak, aspen, basswood, birch and willow. The caterpillars normally emerge in spring through mid-May, depending on when hardwood trees start to bud. Gypsy moth larvae can come in a few different colors, and they are very hairy. They will go through a series of molts to increase in size before turning into gypsy moths.

    Oakworms

    • A few different types of oakworm caterpillars in Michigan have been known to feed on oak leaves and trees. Orange-striped oakworms are black with orange or orange-yellow stripes that run the length of the body. They also have two horn-like projections on their heads. They can be 2 inches in length, and normally feed on oak trees from late July through August. Red-humped oakworms are light in color with a round, red head. They have a hump that is near the bottom of the abdomen. They reach a maximum length of 1 ¾ inches. These caterpillars feed late in the summer and normally do not affect tree health.

    Cankerworm

    • There are two types of cankerworm caterpillars in Michigan, spring and fall cankerworm. Cankerworms are often called inchworms or loopers because of the way they move, which is a slow, inching along as the back of the body comes toward the front to form a loop. They are commonly green, yellow or dark brown. They also have white stripes that run down the length of their body and they normally reach about an inch in length. Fall cankerworms have three sets of legs near the rear of the body, while spring cankerworms have two sets of legs at the back of the abdomen. Both species normally feed during May and June.