Tiny round “shot holes”
A peppering of small rounded pits or holes, especially on rocket, radish and seedlings, points to flea beetles. The 2–3 mm beetles often jump when disturbed.
Hole shape is useful, but the evidence around it is better. Size, droppings, slime, jumping beetles, eggs and the time of day can separate four common causes before you reach for the wrong control.
Start with the quick check ↓Quick check
What to inspect now
Brush a hand over the plant, inspect both leaf surfaces and look beneath the pot or bed edge. Note whether the holes are tiny and round, large and ragged, or accompanied by stripped leaf tissue.
- Main timing
- Flea beetles: spring and summer. Cabbage caterpillars: mainly May to October. Slugs and birds vary with weather and season.
- Plants affected
- Cabbage, kale, broccoli, cauliflower, Brussels sprouts, rocket, radish, turnip and pak choi.
Identification
Signs that narrow it down
Large irregular holes and droppings
Cabbage caterpillars chew through leaves and may enter cabbage hearts. Search for eggs, green or yellow-and-black caterpillars, and dark frass.
Ragged night damage and slime
Slugs and snails leave irregular holes, often on lower leaves and young plants. Inspect after dusk or during damp weather rather than relying on slime alone.
Leaves stripped to stalks
Pigeons commonly tear and strip exposed brassicas, leaving coarse damage without insects or slime. Bird damage is often worst in colder months.
If you confirm it
Useful action, in order
Start with the least disruptive step that protects the crop. The presence of a pest does not automatically justify treatment.
- 1
Match the control to the evidence
Hand-pick caterpillars and eggs, protect seedlings from flea beetles with suitable fine mesh, inspect slugs after dark, and use well-secured netting for pigeons.
- 2
Prioritise seedlings
Young rocket, radish and brassicas can be checked severely. Established plants often tolerate a surprising amount of leaf loss.
- 3
Check mesh carefully
Use a mesh fine enough for the target pest, support it above foliage and seal every edge. Butterflies can lay through netting that touches leaves.
Next crop
Reduce the chance of a repeat
Cover before damage starts
Exclusion works best from sowing or transplanting. Covering after eggs or pests are already inside can trap the problem with the crop.
Rotate covered beds
Some pests can emerge from soil beneath protection. Avoid placing the same vulnerable crop under mesh in the same bed year after year.
Keep young plants growing
Water seedlings consistently and transplant sturdy plants so they can replace modest lost leaf area.
Common questions
Practical answers
What makes lots of tiny holes in rocket and radish?
Flea beetles are the usual suspect when holes are tiny, rounded and numerous and small dark beetles jump from the foliage when disturbed.
Why are there holes when my brassicas are netted?
The mesh may be too coarse, touch the leaves, have an open edge, or have been fitted after eggs were laid. Slugs or soil-emerging pests may also be inside.
Can I eat brassica leaves with pest holes?
Cosmetic holes do not automatically make sound leaves unsafe. Wash produce carefully and discard rotten, badly contaminated or otherwise unfit tissue.
Sources and scope
Evidence behind this guide
SowNext summarises identification, timing and lower-impact management for UK home food growing. Local populations and protected conditions can differ, so confirm the organism before acting.