Common Insects and Mites: Root weevils

categories: Common Insects & Mites Common Problems

revision date: 2022-11-22 03:38

Black vine weevil adult on leaf showing irregular notches along leaf edge.
Black vine weevil adult and leaf damage
Photo by: A.L. Antonelli

Biology

Several species of root weevils can be serious pests of landscape plants including azalea, rhododendron, rose, and strawberry. The black vine weevil is perhaps the most common. Adult weevils create characteristic notchings along leaf margins of countless plant species. The weevil larvae also can be serious pests, particularly in nursery plants. The larvae feed on roots and in some cases girdle crowns and lower stems.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

  • Apply beneficial nematodes which kill the larvae. They are used as a soil drench in moist soils over 52 degrees F (mid-fall in western Washington).
  • Plant resistant varieties when available. Your county extension agent or WSU Master Gardeners can furnish a list.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

Adult control should begin when adults emerge late May-June or when first signs of notching appear on new leaves. A follow-up spray may be necessary about a month later. Beneficial nematodes can be applied to control the larval stage if soil temperatures are warmer than 52 degrees F.

Additional Images