Pests

Flea beetles

Identify Flea beetles: symptoms, possible causes, prevention, and practical actions for 17 affected plants. Small, round holes in leaves

Affected plants Pests

Editorial diagnosis

Diagnosis overview

Flea beetles are small jumping beetles that mainly damage young brassicas and other crucifers. They chew many tiny holes in leaves and can severely slow seedlings in dry, warm weather.

In gardens, Flea beetles can occur on plants including Watercress, Napa cabbage, Choy Sum, Radish. In the available profiles, it is linked mainly with Asian greens, Brassicas, Cabbages. Recorded timing or triggers include April to June, Months: 5, 6, 7, 8.

The recorded risk level is medium. Heavy damage can quickly limit growth in small seedlings.

Inspect leaf undersides, shoot tips, and the soil around the plant at different times of day. Eggs, larvae, droppings, webbing, or slime trails are often more diagnostic than one damaged leaf.

A common mistake is to treat feeding damage without checking the animal, eggs, larvae, time of activity, and affected plant parts.

At a glance

Plants

Risk

medium

Season

April to June, Months: 5, 6, 7, 8

Scientific name

Phyllotreta spp.

Typical signs

Many tiny round holes
Shot-hole pattern
Small dark beetles jump away
Seedlings grow poorly
Worse in dry warm weather

Possible confusion

Slugs: Slug damage is larger and slimy; flea beetles cause tiny dry holes.
Cabbage white butterfly: Cabbage white caterpillars eat larger areas and visible larvae are present.

Immediate actions

Protect seedlings with fleece or mesh
Keep soil evenly moist
Replace badly damaged seedlings
Reduce cruciferous weeds
Check early

Prevention

Cover immediately after sowing
Rotate brassica crops
Encourage strong seedlings
Avoid drought stress
Do not let beds dry out

Flea beetles

Diagnosis overview