Q: What is causing my sycamore leaves to crinkle and curl?
A: Thank you for bringing in some samples of your tree damage. It would have been difficult to locate the small, white cocoons and then identify the insect without seeing those samples. The caterpillar is probably from the Sycamore moth, Halysidota harrisii. The adult moth has a hairy, yellow body, with solid white underwings and black and white markings on the larger upper wings. The caterpillar has chewing mouth parts and they chew on the leaves of sycamore, hickory, poplar and maple. They usually cause very little damage unless their populations become large, which has occurred this year. When the caterpillar numbers are substantial, then they have been known to feed on other prized ornamentals such as Japanese maple, rose, apple, and live oak.