Ways to see no weevil
Vine weevils are the scourge of any gardener who grows plants in pots. The adult beetle is a leaf-eating nuisance and their subterranean larvae gnaw through roots, checking a plants growth and, in extreme cases, causing it to die. Adult beetles are generally active after dark, but can be found skulking under leaves or in debris, like fallen leaves.
To keep numbers low regularly check around plants during daylight hours and sweep up rubbish. The best way to protect pots from attack by larvae is with a biological control or chemical pesticide. Apply as a preventative. Don’t wait until plants actually show signs of attack as by then it will be too late. nemasys Vine Weevil Killer (available online) contains nematodes, a microscopic worm that hunts down, attacks and kills the larvae. Apply when compost is 12˚C or above and it will protect plants for four months.
An alternative is to drench compost with a pesticide. Provado Vine Weevil Killer 2 or Bug Clear Ultra Vine Weevil Killer. These should be mixed with water and delivered with a watering can to compost. Pesticides will protect plants for between two to four months.