Plant Problem Diagnostic
Vine Weevil: Identification and Control
The short answer
Vine weevil damage comes in two forms: adult weevils chew irregular notches out of leaf edges in summer, while the far more serious damage is done underground by their C-shaped, legless white grubs, which eat roots and can cause a container plant to wilt and collapse. Plants in pots and containers are especially at risk, and notched leaves on evergreens such as rhododendron are a common early sign.
For the root-eating grubs, a biological control of pathogenic nematodes is the main option and is well suited to containers. Apply it in late summer to early autumn (August or early September) when the potting media is warm enough for the nematodes to work and before the grubs grow large. You can also tip out pots and pick off grubs by hand when repotting, and remove any adults you find at night.
How to recognise vine weevil
Adults are dull black, slow-moving, flightless beetles about 9mm long that feed at night, notching the edges of leaves. The grubs are plump, C-shaped, legless and creamy-white with a light brown head, found in the compost around roots. Notched leaves on thick-leaved evergreens such as rhododendron are a useful warning that adults are present, but it is the grubs eating roots that kill plants.
- Adults: dull black, 9mm, notch the edges of leaves in summer (feed at night)
- Grubs: C-shaped, legless, creamy-white with a brown head, in the compost around roots
- Container and houseplant plants are most at risk; sudden wilting or collapse can mean root damage
Treat the grubs with nematodes
- 1Time it right — Apply pathogenic nematodes (Steinernema kraussei, Heterorhabditis species and others) in August or early September, before grubs grow large enough to do serious damage.
- 2Watch the temperature — The potting media must be warm enough: roughly 5-20C for Steinernema species and 12-20C for Heterorhabditis species. They work best in open, lighter potting composts.
- 3Check pots by hand — When repotting, tip out the rootball, remove as many grubs as you can find, and refresh the compost.
- 4Deal with adults — Inspect plants after dark and remove adult weevils; a nematode-based adult trap placed on the soil under damaged plants is also available.
Protect containers and houseplants
Because vine weevil thrives in pots, it is a frequent problem for container displays and indoor plants. Inspect new plants before bringing them in, and if a potted plant collapses unexpectedly, check the rootball for grubs before assuming it is a watering fault.
✔ Notched leaves alone rarely kill a plant; treat them as a signal to check the compost for grubs and plan a late-summer nematode application.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- RHS — Vine weevil — Adults eat leaves leaving irregular notches on margins in summer, especially on thick-leaved evergreens like rhododendron; grubs eat roots, particularly in containers; nematodes (S. kraussei, H. megidis, H. bacteriophora, S. feltiae) applied August/early September at soil temperatures of 5-20C (Steinernema) and 12-20C (Heterorhabditis); repot and remove grubs by hand; nematode adult trap available.