Adult flea beetles are very tiny—just 1/10 inch long. They're black, brown, or bronze with enlarged hind legs. They jump like fleas when they're disturbed. The larvae live in the soil and are thin, white, legless grubs with brown heads.
Where they live
Flea beetles are found throughout North America.
Their life cycle
Adults emerge from the soil in spring to feed and lay eggs on the roots of plants. They die out by early July. The eggs hatch in about a week, and the larvae feed for 2 to 3 weeks. They pupate in the soil, and the next generation of adults emerges in 2 to 3 weeks. These pests produce up to four generations a year before the final generation of adults settles down for overwintering.
Plants they attack
Flea beetles attack most vegetables, particularly cabbage-family plants, potatoes, and spinach. They also feed on flowers and weeds.
Why they're a problem
You can recognize flea beetle damage by the small, round holes the adults chew through leaves. These beetles are most damaging in early spring, when heavy infestations can actually kill seedlings. Larger plants usually survive and outgrow the damage, unless they were infected with a plant virus spread by the beetles. Larvae feed on plant roots.
Organic damage control
- Plant susceptible plants as late as possible to avoid the most damaging generation.
- Cover seedlings and potato shoots with floating row covers until adult beetles die off.
- Lightly cultivate the soil around plants before and after planting to destroy any flea beetle eggs and larvae in the soil.
- Flea beetles like to hide in cool, weedy areas. Prevent them from hopping onto your susceptible crops by surrounding the crops with a 3-foot-wide strip of frequently weeded bare ground.
Confuse the beetles by mixing up your plantings. Surround their favorite food plants with flowers and herbs like Queen Anne's lace, dill, and parsley, which attract beneficial insects.