June bugs, also called May or June beetles, go through a life cycle that spans one to three years. Adult beetles emerge from the ground at the end of spring or start of summer. After feeding for several weeks, they lay their eggs in the ground. After two to three weeks, grubs hatch. The grubs burrow deep underground to survive the winter. In the spring, they come closer to the surface, where they pupate and emerge as adults.
Some June bug grubs spend one to two years underground before pupating and becoming adults. Thus, lifespan can vary dramatically.
Adult June bugs feed on the leaves of trees and shrubs, making them a pest for gardeners. June bugs can cause patchy, tattered foliage that weakens or occasionally kills the plants they have fed upon. June bug grubs do not eat foliage, but they do eat roots and organic matter from the soil. The grubs can occasionally damage lawns and harm crops such as corn, potatoes or strawberries.
June bugs and Japanese beetles share a similar appearance and life cycle, but they are separate species. Japanese beetles are invasive, and due to their high population levels across the eastern United States, they typically cause more severe damage than June bugs.