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Flea beetles: how to recognise and treat it

Pest

Flea beetles — Photo: Bob Peterson from North Palm Beach, Florida, Planet Earth!, CC BY-SA 2.0, Wikimedia Commons

Symptoms

Many tiny round pits and holes in the leaves (a shot-hole look); the pits often do not go right through and dry pale brown.
Tiny beetles, 2–3 mm, black or metallic green or blue, some with a yellow stripe, that jump away when the plant is disturbed.
Seedlings and fresh transplants are hit hardest and can be stunted; older plants are rarely harmed unless beetles are numerous.
On potatoes the larvae can bore narrow tunnels in the tubers.

Organic treatment

Cover seedlings with insect-proof mesh or fleece, sealed at the ground; on eggplants use hoops so the cover does not lie on the plants.
Spray kaolin clay, which dries into a barrier that cuts feeding; reapply after rain.
Dust plants with diatomaceous earth or spray neem for serious infestations.
Encourage birds, frogs and ground beetles, which eat the larvae and some adults.

Chemical treatment

Pyrethrins or spinosad for serious infestations, repeated as needed; do not spray plants in flower, follow the label dose and pre-harvest interval.

Reference information, not a guarantee. Read and follow the label of any product: dose, safety and the days to wait before harvest.

Prevention

Rotate crops.
Clear or dig in weeds and crop debris in autumn, where the adults overwinter.
Keep seedlings covered until about the sixth leaf; older plants suffer much less.
Keep young plants growing fast — fertile soil, regular watering — so they outgrow light feeding.

Plants it affects

Sources

Figures checked against these sources.