Flea Beetle is a minor pest that affects kale, broccoli, cabbage in Scotland. Here is what it looks like, how to spot the damage, and which controls have been tested.
🌱 Plants at risk
Flea Beetle also affects these crops in our grow guide:
Symptoms
Small rounded holes in the foliage, especially on seedlings. Damaged areas dry up and turn pale brown. Seedlings are particularly susceptible.
Controls: what actually works
Every method below is graded by evidence, not by how often it gets repeated. Where a claim has been tested and failed, we say so plainly.
Tolerate the damage on established plants
Populations can be tolerated, especially on larger brassicas where the outer leaves are discarded, since the beetles usually have a limited effect on the parts you eat.
Insect-proof mesh, ultrafine (0.3-0.6mm)
Growing susceptible crops under insect-proof mesh may keep the beetles out. Ultrafine mesh (0.3-0.6mm) gives good protection against flea beetles and other very small invertebrates. Standard mesh (1.3-1.4mm) cannot be relied on against them.
Encourage wildlife — birds, frogs and predatory ground beetles
Encourage birds, frogs and predatory ground beetles, which eat the larvae and sometimes the adult beetles.
Scottish grower notes
Flea beetles are most active in warm, dry, still weather and are knocked back by rain — so Scotland's cool, wet springs give emerging seedlings some natural protection. The risk window is a dry, warm spell while brassica and salad seedlings are still small; cover those with fleece or fine mesh until they are growing strongly.
Farm Advisory Service (FAS) Scotland crop-health guidance (2020); the biology is general, but the wet-climate framing is directly relevant to Scotland.
Frequently asked questions
What should I do first if I find flea beetle in my garden?
Start with tolerate the damage on established plants. After that, insect-proof mesh, ultrafine (0.3-0.6mm). The full list of evidenced controls is above, each graded by how much evidence supports it.
Will flea beetle kill my plants?
They rarely kill established plants. The damage is usually cosmetic on outer leaves, and natural predators often bring numbers under control without you doing anything.
Should I just leave flea beetle alone?
In most gardens, yes. flea beetle are food for birds, wasps and predatory insects, and a healthy garden carries some without trouble. Tolerance is also the official position now, and the stance box above sets out that reasoning in full.
Sources
3 sources, recorded with what each was used for
- RHS1: tolerance advice and its reasoning, seedling susceptibility, small rounded holes and pale brown drying, mesh, birds/frogs/ground beetles
- RHS1: ultrafine 0.3-0.6mm for flea beetles; standard unreliable
- FAS Scotland14: flea beetle is suppressed by wet weather and most damaging in warm, dry spells