Bay County Building
515 Center Avenue
Bay City, Michigan 48708-5941

Gypsy Moth Caterpillars Hatching

 Over the weekend Gypsy Moth caterpillars began to hatch throughout Bay County. Like the rest of us, the tiny 1/8th-inch caterpillars have been waiting for warmer weather to aid their development. After resting for a few days, the caterpillars will move their egg masses and begin searching for food. Some will settle on the trees where their egg mass spent the winter, while others will spin a long silk thread and "balloon" to new trees where they can find more food. At this time of year, homeowners generally find the tiny caterpillars on laundry and other items left outdoors. 

 Any questions should be directed to Alicia Wallace, Bay County Gypsy Moth Suppression Program Coordinator, at 989-895-4195 or via email at


Figure 1 - Two egg masses with Gypsy Moth caterpillars; the one to the left has a few caterpillars while the other is completely covered with the tiny black caterpillars.