Basic Tree Care: moth

Gypsy Moth

What is it?

The Gypsy Moth is another species of pest that was brought to the U.S. by accident. Since it's introduction, it has devastated much of the eastern states and caused roughly $868 million in damages. Starting as an egg being laid anywhere with protection during late fall, they hatch in the spring.

The larvae stage

What does it do?

During the first three stages of it's life (seperated by molting and growing in size), the larvae feed on the leaves of their host tree. In the first stage, they take tiny bites out of the leaves, just as much as they need. In the second and third stages they eat the leaves, from the edges to the center. This is the time that they are most damaging to hardwood trees, especially Oak trees. You usually won't see them active during the day unless the infestation is very dense. On minor cases, they feed on the top of the tree at night and rest during the day. If there is a large amount of them infecting the tree, you may see them active all hours of the day. In early to mid June they start building a cocoon. Usually these are located in bark flaps, under branches, basically anywhere providing good protection. When they emerge 7-14 days later, they are fully matured adults. They have now become the moths that we all know and hate. The males emerge first, and fly around look for a mate. The females (in most species) are flightless. Once the females emerge, they emit a pheromone to attract the males. After reproduction, they both die. And so the cycle repeats.

Adult male Gypsy Moth

Adult female Gypsy Moth

How to manage it:

You're best bets are killing the egg masses that you find on the trees or in some cases, anywhere else that provides protection. Destroying one egg mass can kill up to 1000 potential caterpillars. But there are actually a few ways to get these guys:

Hire an exterminator. Usually your local tree care professionals know how to deal with them and when.

Buy a gypsy moth trap. They can be pricey, but the may be worth it.

Short on money? Luckily there's a few homemade tricks you can do to help:

Wrap duct tape around the tree at chest height, then smear "tanglefoot" on the duct tape. The caterpillars can try to cross it, but they wont get far before they get stuck.

Wrap some burlap around the tree and spray it with insecticides. As they cross it, it will soak into their bloodstream and kill them.

Using burlap again, wrap it around the trunk and flip the top half down, creating a barrier for them to rest during the days. Each day, go lift the flap and kill whats under it. This is the cheapest method, and works decently well.