Palestriped Flea Beetles

Are you seeing small holes in the leaves of your garden plants? It may be palestriped flea beetles.

Severe damage to common bean by palestriped flea beetles (Whitney Cranshaw, CSU, Bugwood.org) CC BY 3.0

Palestriped flea beetles (Systena blanda) feed on artichokes, cabbages, and radishes. Beans, carrots, sunflowers, and other edibles are also at risk. Likely, you won’t even see these culprits unless you look closely.

Like other flea beetles, palestriped flea beetles are small insects with large legs for jumping. And they can fly. But they feed on the underside of leaves, so it’s easy to miss them until you start seeing those holes.

Palestriped flea beetle description

Unlike their close cousin, the striped flea beetle (Phyllotreta striolata), and somewhat contrary to their name, palestriped flea beetles have a distinct white band down each wing. Striped flea beetles have wavy gold markings. Both species are only 1/8 of an inch long and tend to be brown with relatively long antennae.

Palestriped leaf beetle (Whitney Cranshaw, CSU, Bugwood.org) CC BY 3.0

Striped flea beetle (Sanja565658) CC BY-SA 3.0

Eggs are elliptical and pale yellow, larvae are white with dark heads, and pupae are small and cream-colored.

Palestriped flea beetle lifecycle

Mated females lay eggs in the soil near the base of food plants each spring. When they hatch, larvae move into the soil where they feed on roots for 2 or 3 weeks before pupating. Pupae match hatch mid-summer through early autumn. There can be up to three generations each year.

After pupating, adults emerge and begin feeding on the underside of leaves. As temperatures drop, adults look for sheltering dirt clods, plant debris, and weeds to protect them through winter.

Palestriped flea beetle damage

While the larvae chew on the roots, adult beetles are the ones that cause the most damage. Palestriped flea beetle feeding looks a lot like shot hole disease. It can also be mistaken for cavity spot. As beetles gnaw on the underside of leaves, the damaged areas die off and create small irregular holes. When this feeding occurs on seedlings and young plants, the damage can significantly reduce yield over the life of the plant or kill them outright.

How to control palestriped flea beetles

Pesticides generally don’t work against flea beetles. You can reduce the likelihood of them setting up shop in your garden by keeping attractive weeds away from your plot. By attractive, I mean members of the same plant families the beetles prefer. You can use that same logic turned around by employing trap crops to lure palestriped flea beetles away from garden plants you’d rather they left alone.

Monitor seedlings twice a week for signs of palestriped flea beetle feeding. Knock any beetles you find into a container of soapy water. Once plants are established, a little damage won’t cause significant problems.