Winter moth fall tree banding    2015

Winter moth is an invasive pest introduced into North America from Europe. With no natural enemies, the population is exploding and the caterpillars devastated Rhode Island trees this spring. The adult winter moths come out from late November through December. Throughout Rhode Island at this time you may see small, dull gray moths attracted to porch lights in large numbers, especially on warm evenings and on some roads you’ll see clouds of moths in headlights. These are all male moths – females have tiny wings and cannot fly. Females emerge from the ground and scramble up nearby tree trunks where they will mate and lay eggs. In the spring, when the caterpillars hatch, they wriggle into swelling buds and begin feeding.

Trying to control male moths is useless; pesticide sprays will be a waste of effort and could harm other insects. It may be helpful to trap female moths with tree barriers to stop them as they climb up trees. It’s unknown how effective tree banding is. It depends on many things including how many trees are in an area and the size of the winter moth population. Tree banding will probably be most successful in yards with very few trees, no woods nearby, and a moderate winter moth population.

Tree bands should be in place by mid-November. Tree bands can be homemade or purchased from some garden centers. Commercial products include BugBarrier and Tree Wrap. BugBarrier can be purchased from Tree Shelter in Attleboro Falls, MA. Homemade bands can be made by spreading a sticky substance, such as Tree Tanglefoot, to duct tape or plastic wrap attached to tree trunks. Don’t coat tree trunks directly with Tanglefoot or any sticky substance.

Where there is a large population of winter moths, dead moths can completely cover the sticky surface and then female moths can easily walk over dead moths. It may be useful to have two tree bands per tree so you can monitor if female moths are climbing past the first barrier. If this happens, replace the barrier.

When a female moth encounters a tree band she tends to lay many eggs right below the tree band. For this reason, tree-banded tree trunks should be sprayed with a dormant oil next March to kill eggs laid on the trunk.