The grape flea beetle (or steely beetle) is a shiny, metallic dark blue. It may jump when disturbed. The insect overwinters as an adult. This stage feeds directly on young buds, beginning when conditions warm in the spring. Vineyard borders adjacent to woods or other protected areas are most affected. Adults damage swelling buds by hollowing them out. Their damage may be confused with cutworm damage because both species feed during bud swell. The level of injury varies from year to year and is worse when cool temperatures slow bud development.
Larvae are yellow-brown with a dark head and feed on clusters and leaf surfaces. Damage is greatest at borders but rarely reaches economic levels.