Biological control of vine weevil

Several species,of pathogenic nematodes, including  combinations of species, can be purchased from biological control suppliers. Suitable for use in pots and in open ground, these microscopic organisms enter vine weevil grub bodies and infect them with a bacterial disease. Apply in late summer or early autumn on moist soil before the grubs are large enough to cause significant damage.

Nematode traps are also available for vine weevil control and should be place on the ground around damaged plants in summer. Adults enter the trap and are infected with the nematodes.

Encourage natural predators that feed on vine weevils and their grubs. These include birds, frogs, toads, shrews, hedgehogs, and ground beetles. 

Hedgehogs like dense undergrowth and grasses for hiding and nesting. You can also build or purchase hedgehog homes. 

Frogs and toads can be encouraged into the garden by providing a pond or other still water feature where tadpoles can develop. Construct the pool so at least one side gradually slopes up to dry land. This allows young amphibians to leave the water in midsummer once the tadpole stage is over. Small amphibians can be heavily predated by birds, so grow plants around the pool to provide some cover.

Provide a place for frogs and toads to overwinter. Log piles are great shelters but frogs, toads and newts will also find suitable places in hedge bottoms, compost heaps, and under stones. They may aslo hibernate in the bottom of ponds. To avoid disturbing amphibians, especially in the hibernation period, ponds should not be cleaned out unless absolutely necessary.