Caterpillars
A number of caterpillars feed on new growth in springtime. We find many western tussock moth, fruittree leafroller and California oakworm caterpillars on native oak trees. These insects overwinter as eggs, hatch into larvae (caterpillars) in springtime, then pupate in early summer before becoming adult moths that mate and lay eggs to start the cycle anew. People usually notice the caterpillars when they drop down on strings from the canopy or crawl down the trunks to pupate on nearby structures. Many beneficial insects either parasitize the larvae (such as tachinid flies), or the pupae or eggs (such as tiny wasps).
Various birds feed on both larvae and eggs. In problem areas, green lacewing larvae can be released to eat the first caterpillars that appear, and egg masses together with pupal cases can be "power-washed" from tree trunks in late summer.
