Photo 1: Redheaded flea beetle on turtlehead (Chelone). Note the irregular brown patches of feeding damage on the leaves.
Redheaded flea beetles feed on a wide variety of plants, especially agricultural crops such as corn, soybeans, cabbage, and alfalfa as well as many weeds. They are now being found in the landscape and nurseries for seemingly the first time where they have been reported feeding on hydrangea, viburnum, and other shrubs as well as many perennials.
Adults typically hatch in July and August and are active on plants until September.
Their feeding can cause small holes which can create a skeletonized appearance in the leaves. In plants with thicker leaves, they remove irregular patches of leaf tissue which eventually turns brown. We have received reports of these beetles in the landscape in Hennepin, Clay, and Carlton counties although they are undoubtedly in other sites in the state.
These flea beetles typically cause little damage to plants. The injury people see on their shrubs and perennials are generally going to only affect the appearance of them. If it does become desirable to treat redheaded flea beetles, they should be easily managed with most residual insecticides.
Redheaded flea beetles have been particularly abundant this year. It is unclear whether this is an emerging landscape problem or a temporary blip. We would be interested to hear any reports of this insect attacking landscape plants. If you encounter redheaded flea beetles, send an e-mail to the author (firstname.lastname@example.org) and report what plants it is attacking and the location. Also include a picture if possible.