Winter moth caterpillars are notorious for their ability to quickly strip a budding tree of its young foliage and buds, and those leaves that they do not devour entirely may be left with huge holes and little chance of survival. These small, green caterpillars turn out in vast numbers when they infest an area and attack a wide variety of deciduous trees and plants, including oak, ash, maple, apple, elm and cherry trees in addition to blueberry and other bushes.
There are a few different ways to combat the leaf-destroying winter moth caterpillar. Early treatment may be the best way to prevent extensive damage because the caterpillars typically feed during the spring months before re-emerging as fully-fledged moths during the late fall and early winter. One early treatment method involves spraying potential target trees with horticultural oil. This action should be performed in early spring, and the spray should be concentrated on the trees' bark. This will suffocate the moth's eggs before they hatch, reducing the chance that any leaf damage will occur. Once eggs have hatched, the caterpillars can be killed with a bacteria called bacillus thuringiensis.