Flea Beetles

Image Gallery The three-spotted flea beetle

For many years we noticed the tiny holes in the leaves of different garden plants before we actually went investigating. We were continually frustrated at seeing only the holes, but not actually seeing the bugs. It was after reading about these little mysteries that we realized flea beetles are given the name "flea" because they have great jumping back legs and actually leap off their chosen leaves when big monsters, like gardeners, approach. We hadn't been observant enough to notice this escape maneuver.

You have to look closely to see these tiny creatures, members of about 370 species of one subfamily of the beetle order Coleoptera. The adults can be from 1/16 to 1/5 of an inch long, depending on the species. Under a hand lens, the different species usually will be a dark color, but a few species will show some light-colored stripes. At least a dozen different species are happy munching on common garden crops. Some species will feed on more than one plant crop, but many are tied to single crops or closely related crops.

Flea beetles are found throughout North America. Adults overwinter and lay eggs in early spring on or in the soil near the base of the host plant. The egg-larval-pupal stages take four to five weeks, after which the new adults emerge in search of fresh greenery. The thin, white larvae do some feeding on roots of the host plants and leave snaky markings on potatoes, but the adults are the hungriest competitors for our garden groceries, and most damage is done to the foliage. Adults are attracted to young plants and chew the typical "shot-holes" in the underside of leaves. Some plants that attract these beetles are cole crops, corn, eggplant, grapes, potatoes, spinach, sweet potatoes, tobacco, tomatoes and cucumbers.