Elm leaf beetle overwinters in the adult stage in protected places like cracks, crevices, under rough bark and in buildings. Inside homes, they can become a nuisance in the fall and spring as they move into and out of the house. The adult beetles become active when the new elm leaves start to emerge in the spring. Heavily infested leaves turn brown as if scorched by fire and often will drop prematurely. After several weeks of feeding, the larva crawl down the trunk or fall to the ground where they pupate.
Adults emerge to start the second generation.
Normally the second egg hatch occurs about mid-July though this may vary depending on the year and area of the state. Often a single application made to control the first generation is all that is required. Specific time varies with the season and different areas of the state. Soil injection of systemic insecticides can also be used but should be done by commercial arborists and nurserymen. Though adult beetles that invade homes can be a severe nuisance, they do not feed or damage food or furnishings.