Vine weevil

The Vine weevil (Otiorhynchus sulcatus) is native to Europe, but common in North America as well. This weevil is a pest of many garden plants, causing the most damage on evergreen trees and shrubs.

The adult weevil is black with fused wing covers, and is unable to fly. Adults feed at night on the outer edges of leaves, causing the leaves to have a notched margin.

Grubs live below the soil surface, and feed on the roots and on the cambium at the base of the trunk.

Symptoms
The damage produced by the adult weevil is usually not serious, and is most recognizable by notched or crescent-shaped scars along the edges of the leaves or needles. It is in the larval stage that the weevil is most destructive by consuming tender feeder roots. The foliage of infested plants will turn yellow or brown and can wither or otherwise show signs of poor growth. If left uncontrolled, a severe infestation of the vine weevil may ultimately kill the host plant.

Organic
The soil dwelling grubs can be controlled using predatory nematodes which can be bought from some garden centres, and by mail order. They are simply mixed with water, and watered onto the soil. The Pathogenic nematode (Steinernema kraussei) can be applied as a drench to the soil around the plants, ideally in August-September.

Adult weevils can be controlled by using sticky barriers on the trunks of affected plants, as the weevils return to the soil each day.

Adults can also be manually removed from plants at night when they can be found feeding on leaf edges. Use only a dim torch or candle light to search by, as they will drop to the ground if startled by bright light.

Adults may also be controlled using the fungus Beauveria bassiana, which is a biocontrol.

Chemical
No chemical control is available.