Plant Information

Plant Information

Black Vine Weevil

Susceptible Plants
Conifers, especially yew (Taxus); broad-leaved evergreens, especially rhododendron, azalea (Rhododendron), euonymus, and English ivy (Hedera); deciduous plants, including climbing hydrangea; and greenhouse plants including impatiens, cyclamen and gloxinia (Sinningia).

Description & Symptoms
Weevils are beetlelike insects that feed on plant roots in their larval stage and plant leaves in their adult stage. Adult weevils are rarely seen because they feed at night and hide during the day in dense foliage, plant litter, or mulch. The black vine weevil makes a characteristic C-shaped cut when it eats the margin of plant leaves. When insect populations are high, every leaf or needle on a plant can become notched.

Timing & Life Cycle
Adult weevils usually feed on leaves during June and early July. The larvae are most damaging in late May and early June as they feed extensively on roots before pupating into adults. Root damage occurs again in August and September when a new generation of larvae hatches underground and begins feeding on roots. There is only one adult generation per year.

The visible notching of leaves is rarely harmful to plants, although it is unsightly. Root feeding by the larvae causes more serious damage and in severe cases can kill plants.

Treatment & Solutions
It is difficult to control black vine weevil without using chemical insecticides. Insecticides are applied at the first sign of notched leaves, usually in early June.

For more information about black vine weevils, call the Plant Information hotline at (847) 835-0972.