Redhumped caterpillars pass the winter as full grown larvae in cocoons on the ground.
Eggs hatch into larvae that begin feeding on leaves. There are at least three generations each year in northern California. They do not web leaves. Insecticide sprays applied for other pests often keep these leaf-eating caterpillars in check. If insecticide treatments are required, localized treatments on individual trees applied when evidence of caterpillars is first observed are generally all that is necessary.