Vine weevil: how to recognise and treat it

Pest

Symptoms

Irregular notches in leaf edges in spring and summer, most visible on thick-leaved evergreens such as rhododendron.
Plants wilt and die from autumn to spring because the grubs have eaten the roots; plants in pots suffer most.
Plump, C-shaped, white, legless grubs up to 10 mm long with light brown heads among the roots.
Grubs also bore into cyclamen and begonia tubers and into the stem bases of cacti and succulents.
Dull black, pear-shaped weevils about 9 mm long with dirty-yellow flecks, feeding at night; they cannot fly.

On mild evenings pick the weevils off plants and walls by torchlight; shake shrubs over an upturned umbrella or sheet to collect more.
Repot plants in pots, removing as many grubs and as much old compost from the roots as possible.
Water parasitic nematodes (Steinernema kraussei, Heterorhabditis megidis, H. bacteriophora or S. feltiae) into moist soil or compost in August–early September, when it is warm enough (5–20 °C for Steinernema, 12–20 °C for Heterorhabditis); they are safe on edible plants.
In a greenhouse, put sticky barriers around pots or on the staging; on shrubs, a sticky band on a wrap around the trunk stops the flightless weevils climbing.

Spinosad sprayed on the leaves in the evening, about a week after fresh notching appears; repeat after 7–10 days if needed. Check the product is approved for the plant in your country and follow the label dose and pre-harvest interval.

Reference information, not a guarantee. Read and follow the label of any product: dose, safety and the days to wait before harvest.

Check susceptible plants often, especially those in containers, so you act before many grubs build up.
In a greenhouse, look under pots and staging, where the weevils hide by day.
Encourage birds, frogs, toads, shrews, hedgehogs and ground and rove beetles, which eat weevils and grubs.
Leaf notching alone rarely harms the plant and can be tolerated — the grubs at the roots do the real damage.

Figures checked against these sources.