The gypsy moth was brought to the east coast of the United States way back in 1962 in a misguided attempt to breed a hardy silkworm. Since that time, they have continued their slow relentless march westerly, and yes, we now have a resident population here in Watertown. If left unchecked, the Gypsy moth population can increase at a very rapid rate, producing so many larva (caterpillars) that they can defoliate an entire forest. This lose of leaves can leave the trees weakened and vulnerable to boring insects and disease outbreaks. During periods of high gypsy moth populations trees will literally rain caterpillars, becoming a nuisance to homeowners with hundreds of thousands of caterpillars crawling around.
During the winter of 2001-02, the Park, Recreation and Forestry Department discovered a fairly large number of gypsy moth egg masses concentrated in a small area of Washington Park. This is not the first gypsy moth sighting in Watertown, but the Washington Park infestation is the most significant concentration of the insect observed to date. A sizable gypsy moth population has also been discovered on the Bethesda Lutheran Homes property.
Wisconsin has not yet experienced the widespread defoliation of its trees like many states in the northeast, but the potential certainly exists. We may never eradicate the gypsy moth, but there are a number of steps that can be taken to slow down its progression through the state and minimize the damage to our trees. Killing or removing egg masses is the most effective physical method of reducing the population of gypsy moths in your yard. Each egg mass destroyed is 600-1000 caterpillars you won't have to deal with next spring. Each year after leaves have fallen, examine your trees, outdoor furniture, play equipment, and even the exterior of your house. They are often found in cracks or hidden spots, such as under shutters and loose bark. There are several methods recommended for killing the egg masses. Please contact the department office for more details. Egg masses are roughly tear-drop shaped, 1 to 1 1/2 inches long, yellowish-tan, and look like felt (see photos).
Watertown Forestry Department officials would appreciate the public's help in identifying other possible areas of infestation. It is important to note that if the caterpillars have a web, they are not gypsy moths. If you feel you have gypsy moth egg masses or have any questions, please call the department office at 262-8080.