Gypsy Moth in Grand Rapids

JPEG image of Gypsy Moth caterpillar on a leaf

Gypsy moth has been a forest pest in Michigan for over 40 years. This summer, the population and effects of Gypsy moth are higher in Grand Rapids than previous years, mainly affecting Oak trees. Below, we've explained the situation, our plan of action, and what you can do to help.

Overview

The highest concentration areas affected in Grand Rapids are Indian Trails Golf Course, Heritage Hill, around Oakhill and Woodlawn cemeteries, and the area west of Richmond Park. Currently, the Gypsy moth population in Grand Rapids is growing quickly, which is common.

The treatment window for this year has passed, and caterpillars are nearly done eating, so no immediate action will be taken. We expect the population to crash as naturally occurring viruses and bacteria spread among the caterpillars.

Even though the effects on trees may look devastating, we expect the leaves to regrow this season once the Gypsy moth population crashes. When the caterpillars become moths, they don't feed on trees.

Future Action

We've explored moth trap options to predict caterpillar populations and are conducting winter egg mass surveys to identify high-concentration areas. We're looking into the possibility of spring insecticide applications to control outbreaks. Below are recent Gypsy Moth updates:

How You Can Help

If you encounter a tree affected by Gypsy moth, there are a few things you can do to help.

  • Water the tree(s) throughout the summer to help with leaf regrowth.
  • Treat the tree(s) with an insecticide like B.t. caterpillar and webworm control.
  • Contact a local forester for treatment options. Foresters can be found at the International Society of Arborculture's website.
  • Report sightings to the Michigan Animal and Plant Health Inspection Service (APHIS) branch.

Additional Resources