Spongy moth - an insect species that is invasive to trees - is experiencing a local resurgence due to the dry spring conditions of the last several years.

The dry conditions have reduced the effect of the Japanese fungal pathogen Entomophaga maimaiga, which has been successful in controlling the growth of gypsy moth populations in North America.

Residents are encouraged to help the City of East Lansing monitor and control this threat through early identification and intervention:

Spongy moth eggs

  • Keep an eye out for presence of large numbers of whitish/tan egg masses on oak trees and other types of trees.
  • A sticky substance called Tanglefoot is available through retailers locally and online. It can be applied to tree trunks in the spring to capture caterpillars, reducing their impact to trees. Wrapping a 12-inch strip of burlap or similar material around the trunk of a tree and securing it in the middle of the strip so that the material folds in half to form a double flap about 6 feet wide can also be helpful in capturing migrating caterpillars. More info.
  • Keeping trees and soil well watered in the spring will reduce tree stress and help E. maimaiga grow, thus reducing the spongy moth population.

Spongy moth


Do you have spongy moth caterpillars on your trees?

Spongy moth caterpillars are 2 inches long and have paired red and blue spots, yellow and black heads and long, dark hairs that distinguish them from other species (see photo above). They start off as clumps of eggs and eventually will hatch into a caterpillar. The caterpillars move up the tree throughout the day, so you will most likely see them at the base of the trunk in the early morning. Residents can report suspected infestations by calling (517) 337-9459.