The tiny larvae burrow through the young leaves which are still folded together in the bud. Then when the leaves unfold and become larger, the insect holes also become larger and the leaves become ragged, distorted, and worthless. As the larvae grow they then feed on the more mature leaves. They feed for about 3 weeks. Then the mature larvae leave the plant and enter the ground to pupate.
Several generations occur each year.
Winter is passed in the pupal stage.