In autumn, caterpillars drop to the ground and spin silken cocoons. They remain inside the cocoons during winter and transform into pupae in spring. May. They mate, and each female may lay over 200 eggs. The eggs hatch into tiny caterpillars that feed, grow, and finally drop to the ground to pupate. There are often as many as four or five generations per year.
Redhumped caterpillars seem to be more abundant after a warm winter.
A number of parasitic wasps, including Apanteles species and Hyposoter fugitivus, use the redhumped caterpillar as a host and on occasion provide an effective natural control. However, in some instances additional control measures are necessary. The simplest of these is to cut off the foliage that contains caterpillars while the insects are still young and gregarious. At this stage only small branches need to be pruned off to destroy a large group of caterpillars. The foliage can then be burned or the caterpillars crushed.