Diagnose by symptom
Holes in leaves
Chewed holes and missing tissue are almost always leaf-eating pests. The usual culprits:
Pests
Slugs and snails
Slugs and shelled snails that feed at night and after rain. Symptoms: irregular holes in the leaves and young seedlings …
PestLarge white butterfly
A large day-flying butterfly with a wingspan of 50-65 mm; the wings are white, the forewings with black tips, and in the…
PestFlea beetles
Tiny (1–3 mm) beetles with black, or black and yellow longitudinally striped, wing cases and strongly thickened hind fem…
PestVine weevils
Weevils 8-12 mm long, black or dark brown, with a short, broad snout, flightless and active at night. Their larvae are w…
PestSawflies
The larvae strongly resemble the caterpillars of butterflies and moths, but have more pairs of abdominal prolegs (six an…
PestColorado potato beetle
A beetle 6–11 mm long with yellow, convex wing cases bearing ten black longitudinal stripes. The larvae are brick-red to…
PestLeaf-roller moths (tortricids)
The caterpillars roll, fold and glue leaves together with a webbing of silk threads, creating shelters in which they fee…
PestBox tree moth
Bright green caterpillars with a black head, black dots and dark longitudinal stripes along the body, growing to 4–5 cm.…
Frequently asked questions
What is eating holes in my leaves?
Irregular holes are usually made by caterpillars, slugs and snails, beetles (e.g. Colorado beetle, vine weevils) and tiny flea beetles. The feeding pattern gives it away: slugs leave slime trails, flea beetles make small round holes in brassicas, and weevils chew notches along leaf edges. Check plants in the evening when many pests feed.
How can I tell if slugs are the cause?
Slugs leave characteristic shiny, dried slime trails on leaves and soil, plus irregular holes at the edges and within the blade. They feed at night and in damp conditions, so damage appears in the morning after rain. Look for them in the evening with a torch, or under boards and pots where they hide during the day.
How do I protect plants from caterpillars?
Regularly check leaf undersides and pick off caterpillars and eggs by hand, especially on brassicas. Cover vegetables with fleece or netting so butterflies cannot lay eggs. Under heavy pressure, a biological product based on Bacillus thuringiensis helps and is gentle on bees and beneficial insects.