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Cornell University : Cornell Cooperative Extension
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| Yates Association |
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Caterpillers on Trees |
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There are many types of caterpillars which feed on the foliage of trees. Most caterpillar populations are active in a particular season and populations can vary substantially from year to year. Some Caterpillars like the eastern tent caterpillar and fall webworm form visible nests in the trees. Cankerworms, inchworms and gypsy moth caterpillars do not form webs but, can sometimes hang from individual threads from branches. Damage from caterpillars can vary from small holes in individual leaves to defoliation in severe cases. Many caterpillars feed on preferred trees but, can attack many hosts where populations are high. Caterpillars can be controlled by several methods. The nests of tent caterpillars can be removed when they are first seen. Some caterpillars can be controlled by using tanglefoot or sticky tape on the trunk area. Valuable trees can be protected from high populations of caterpillars by well-timed sprays. Insecticides containing the biological insecticide BT can be helpful if applied to early stage larvae. Insecticides containing Carbaryl and Malathion are labeled for some of these caterpillars, but should only be used in severe situations and only at the correct time for effectiveness. Always read the label. Treatments to full size larvae or defoliated trees are seldom helpful. The fall webworm which appears in trees in August does not cause long term harm to trees. The webs can be unsightly but, the damage occurs late in the season after the leaves have performed their function. Cornell
Cooperative Extension Yates Association |
