| Life Cycle: | The adult beetle is approximately one centimetre long and predominantly black with a long snout. Its wings have parallel ridges running their entire length with the ocaisional patch of yellow hair. The adult black vine weevil emerges in June and begin egg laying at the start of July. The female lays up to 500 eggs which are deposited at the base of host plants. The eggs hatch within two weeks and begin feeding on the host plant's roots. The larvae, which are white with reddish brown heads, will burrow beneath the soil where they will over winter. The larva become active again in May when they feed extensively before pupating. |
| Host: | Over 100 hosts of black vine weevils have been identified. They can pose problems for greenhouse and nursery growers of forestry and ornamentals. Yews, hemlock and Douglas fir appear to be favoured trees. Strawberry and raspberry crops are also preferred hosts. |
| Bio Region: | Northern and eastern United States and Canada. |
| Damage: | The larvae feed on the roots of host plants but can can also girdle and thereby kill the plant or tree by chewing around the stem. |
| Management: | Management of the black vine weevils is very difficult. It has very few natural predators and it spends a good portion of its life cycle under the surface of the soil. In small scale operations hand picking the weevils is possible by providing a hiding place such as a piece of cardboard near the base of the host plant. Weevils have greater survival rates when mulch is used. |
| Controls: | There is some evidence that entomopathogenic nematodes will attack the larvae. The most effective nematode for the job is Heterorhabditis bacteriophora. The nematodes should be introduced in mid to late summer. Beauvaria bassiana is a soil born entomopathogen that is effective in controlling both the adult and larval stages of the black vine weevil. The fungus adheres to the weevil's skelton and essentially grows into it eventually killing the beetle. While the fungus is registered in the United States by OMRI, its use in Canada has not yet been approved. Carabid beetles will help keep small populations of black vine beetles under control; however, they are susceptible to the same control measures.
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