Factsheet: Least-toxic Control of Gypsy Moths
Pest type: Insects
Gypsy moth caterpillars change appearance as they grow. Young caterpillars are black or brown and about ¼ inch (.6 cm) in length. As they grow, bumps develop along their backs along with coarse, black hairs. Each of the 11 sections of a developed caterpillar will have two coloured spots, the first five pairs, blue, and the last six, red. Mature caterpillars can be as long as 2 ½ inches (6.35 cm).
Tree damage is caused by the insect larvae, or caterpillars, which emerge from their eggs beginning in early spring and continuing through mid-May. Gypsy moth caterpillars prefer to eat oak, birch, apple, willow, linden, hawthorn, and sweet gum trees. Older caterpillars may also attack crabapple, cherry, beech, hickory, walnut, hemlock, and pine trees.
Trees maintained in a healthy and vigorous condition are less susceptible to infestation.
Sticky barrier bands keep caterpillars from climbing up the tree trunks. A barrier can be made with sticky gum products that are applied directly on the tree bark.
Sticky tape products are the best trap. for rough bark. Barriers are most effective when placed around the trunk by the first week in April. The barrier should be checked at least once a week, and removed when caterpillars are not seen for several days.
Make a burlap band. Place burlap hiding bands around tree trunks to reduce the number of wandering caterpillars and detect very low population levels. Instructions to make a burlap band can be found here.
Spray egg masses with dormant oils, vegtable based horticultural oils.
Look at your product labels and try to avoid products containing those chemicals listed below:
(A = acute health effects, C = chronic health effects, SW = surface water contaminant, GW = ground water contaminant, W = wildlife poison, B = bee poison, LT = long-range transport)