How NOT to Control Gypsy Moths
One of the most common ways to try to control gypsy moth (Lymantria dispar) populations is to wrap tree trunks with control bands. These are simply burlap skirts that are wrapped around the tree. Gypsy moths feed on the leaves of the trees at night and then climb back down the tree trunk and hide under the bark or leaves during the day to avoid predators. The burlap skirts provide an ideal hiding spot for the caterpillars and they will congregate there in large numbers. This makes it easy to capture and kill them during the day. The burlap itself does not act as a trap, and actually increases the moth’s chance of surviving to adulthood, because it prevents predators like Blue Jays from seeing them. Burlap only works if the caterpillars are removed every few days. So if you are going to put up the burlap skirts, you must be committed to checking them every few days and killing the caterpillars by squishing them or by scraping them into a jar of soapy water so they drown.
We saw thousands of male gypsy moth flying around burlap skirted oak trees in one of the parks in Green Bay, Wisconsin in July of 2010. There were many females actually laying their eggs underneath the burlap. This is unfortunate because now there will be more work to remove egg masses this winter and spring.
Some Links on How to properly use burlap tree skirts:
- WI Gardener video clip http://www.uwex.edu/ces/gypsymoth/collectionband.cfm
- tips on controlling gypsy moth throughout the year: http://www.uwex.edu/ces/gypsymoth/index.cfm?mo=6