GYPSY MOTHS IN LAPEER, MI

Occasional flare-ups of gypsy moth populations are not uncommon around Lapeer due to the number of trees and the species of trees found in the area. We do occasionally receive calls from homeowners that think they have gypsy moth, but it turns out to be less damaging caterpillars – usually eastern tent caterpillars or forest tent caterpillars.

Gypsy moth caterpillars have five rows of blue dots followed by six rows of red dots along its back, front to rear. The eastern tent caterpillar has a white stripe running the length of its back. The forest tent caterpillar has a series of “keyhole” shaped, yellowish dots running the length of its back. Each of these different caterpillar species get rather large and are hairy.

Here’s what to do to determine if you actually have gypsy moth caterpillars and what actions you can take if it turns out you do have gypsy moth caterpillars on your trees.

Do you know what kind of trees you have on your property?

It’s less likely you have gypsy moth caterpillars on your trees if you don’t have any trees they like to eat. Gypsy moth prefers to feed on oak, aspen (poplar), birch, crabapple and willow trees. We have found them feeding on other tree species (even spruce trees), but this is only when their population is at its peak.

Where can you find gypsy moth egg masses?

Look on the underside of tree branches, on tree trunks, under house overhangs, or the underside of bird baths. Almost any object in your yard could have gypsy moth eggs masses on it. Gypsy moth eggs masses are gold, brown, or tan colored, 1 to 1 1/2 inches long, and oval shaped. The egg masses are flattened against whatever they are laid on and are covered with fine hairs.

What can be done to control gypsy moth caterpillars?

In Lapeer, gypsy moth caterpillars start hatching in mid-May with peak feeding injury occurring in mid to late June. The safest treatment for gypsy moth caterpillars is to spray infested trees with Bacillus thuringiensis (B.t) when the caterpillars are small. However, B.t. is not effective for control of gypsy moth when the caterpillars are greater than one half inch long.

Controlling larger gypsy moth caterpillars can be done with any one of several registered traditional insecticides labeled for control of gypsy moths. Most insecticides labeled for control of gypsy moth will work both on contact and leave a residual on the foliage that will control caterpillars that show up after the tree spraying is done.

What if defoliation from gypsy moth caterpillars has already occurred?

Gypsy moth caterpillars are heavy feeders and can consume 100% of the foliage on a tree. A couple years of heavy defoliation can kill even a mature tree in your landscape. All trees infested with gypsy moth caterpillars should be given adequate water and fertilizer to help them recover. Any amount of defoliation from gypsy moth caterpillars may cause some branch dieback, so pruning may also be necessary.