Divisi
Flea beetles
· Insect
Photo: Anak Sago · CC BY 4.0
Tiny, shiny beetles about the size of a pinhead that hop like fleas when you disturb the plant. The adults chew the surface of young leaves, peppering seedlings with small round holes; the pale grubs of some kinds also feed on roots below ground. They build up fast in hot, dry weather and march in from weeds and old crop stubble, hitting your cabbage, covo, kale, rape, eggplant, tomato, sweet potato and amaranth hardest while the plants are still small and tender.
Whitney Cranshaw, Colorado State University, Bugwood.org · CC BY 3.0 us 
Whitney Cranshaw, Colorado State University, Bugwood.org · CC BY 3.0 us
Why it matters
Flea beetles go for your seedlings — cabbage, covo, kale, rape, eggplant, tomato, sweet potato and amaranth — right when they are too small to fight back. A bad attack can cost you up to a quarter of your crop (25%), and it can kill young seedlings outright before they ever get going. Once the beetles have built up in hot, dry weather they keep coming from the weeds and the old crop next door, so if you wait until the leaves look like a sieve you have already lost the tender window when the plant could have outgrown them. The trick is to protect the seedlings early, before the beetles find them.
When to act
seedlings averaging more than 2-3 fresh shot-holes per leaf, or any wilting of very young seedlings
This guidance is general, compiled from published agronomic references including FAO and CABI. Thresholds and timing shift with your crop, your variety and the season.
In much of the region a spray is simply called mushonga — medicine. But a chemical group you cannot name is one you cannot rotate, and a product you did not write down has no pre-harvest interval you can observe. Mushonga, and other farming words →
The full flea beetles field guide
- Identify it
- Scout for it
- Control it
16 field-guide sections in the app
The full guide to flea beetles — every symptom to check, how and when to walk your field looking for it, and the controls that actually work, ranked. Built into your crop plan, so you are told to look before it costs you a harvest.
Crops it affects
Frequently asked questions
How do I identify flea beetles?
The damage you see first: lots of tiny round holes and shallow pits peppered across the young leaves, so the leaf looks like a sieve or like it was hit by birdshot ("shot-holes"). On a badly-hit seedling the little holes join up, the leaf dries brown at the edges, and the whole plant wilts and can die.
When should I take action against flea beetles?
seedlings averaging more than 2-3 fresh shot-holes per leaf, or any wilting of very young seedlings
How do I control flea beetles?
Prevent — raise strong, protected seedlings (cultural, your best non-chemical tool): grow vigorous seedlings and transplant only strong, healthy plants that can outgrow the damage fast. Cover the seedbed with a fine net or floating row cover (a light cloth laid over hoops) so the beetles simply cannot reach the young leaves — this is the single most reliable protection through the tender window.
Which crops does flea beetles affect?
Among the crops covered here: African eggplant, Amaranth, Cabbage, Eggplant, Rape / covo / kale, Sweet potato, Tomato.
Catch it before it costs you a harvest
Divisi builds scouting into your crop plan — it tells you when to walk your field, what to look for at that stage, and what to do when you find it. Free for farmers, works offline.
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