The Tussock Moth is native to North America. The egg masses overwinter near the area where they feed. In early spring, one inch yellow fuzzy caterpillars appear and begin to feed on the foliage of a range of host plants including Birch, Cherry, Apple, Oak, Rhododendron, as well as many other trees and shrubs. They feed voraciously on both old and new foliage. In late summer, the larvae pupate in cocoons on the underside of the foliage and emerge two weeks later as a dark brown moth which will then lay eggs that will continue the cycle again.
To control this pest, we recommend two applications of BT in early spring. BT is a biological product made of a naturally occurring bacterium called Bacillus thuringiensis which kills some groups of insects including the Tussock Moth. This is the most recommended treatment for controlling chewing insects because it does not affect people or pets, and it does not harm beneficial insects such as bees.