Flea Beetles

by Nanette Londeree, Master Rosarian

SIGNS

Small (1/10 inch), black, brown or bronze insect with enlarged hind legs found on leaves, buds and open blooms of many vegetables, fruit (including grapes), flowers, and weeds that jump like a flea

SYMPTOMS

Small “shotholes” in the foliage (adults)
“Snaky” markings on potatoes and other root crops (larvae)

CAUSE

Larvae and adult forms of flea beetles belonging to the family Chrysomelidae, found throughout North America

OPTIMAL CONDITIONS

Typically become active during warm daysMultiple generations per year in warm climatesLike to hide in cool, weedy areas

TREATMENT

Prevention:

Maintain good garden sanitation; control weeds in and around the garden or vegetable area and eliminate, as much as possible, trash in which the beetles can over winterIf present on other vegetable or fruit crops, cultivate frequently to kill eggs and remove infected plants after harvestThick mulches may also help reduce the number by interfering with activity of the root and soil stagesDiatomaceous earth is one of the more effective repellents, applied as a dry powder to the plantsHorticultural oils and some neem insecticides also have some repellent effectEncourage beneficial nematodes

Elimination:

Insecticides should not normally be necessary and are not very effective when populations are highOrganic treatments include garlic and hot pepper sprays, rotenone and pyrethrum, sabadillaSulfur containing pesticides may be repellentGarden insecticides containing carbaryl (Sevin), spinosad, bifenthrin and permethrin can provide fairly good control for about a week 

GOOD GUY / BAD GUY?

Generally only a nuisance for roses; injuries are usually minor and easily outgrown on established plants. May be a more significant pest for the vegetable garden, where seedlings are most at risk. Used as a beneficial for some crop pests.

Photo from the Ohio State University website.

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