Vegetable weevil—Listroderes costirostris obliquus
Weevil larvae are green, legless grubs about 0.38 inch long when full grown. Adults are small (0.38 inch
long) brown or gray snout beetles with a V-shaped spot at the tip of the wings. They cannot fly. Vegetable
weevils have only one generation a year, but adults may live 2 years or more.
Identification of species
Both adults and larvae feed on buds, foliage, and roots of potatoes, tomatoes, carrots, lettuce, and
other vegetables. Adults do not fly, so infestation of new areas takes place slowly and damage within
the area may be spotty. Both adults and larvae are most active at night and can be difficult to find in
the daylight. Young plants may be cut at ground level or defoliated.
Little is known about management for the
vegetable weevil. Young plants can be protected
with cloth. You may be able to prevent localized infestations
from spreading by destroying infested rows or picking
off weevils at night. Sticky barriers can be used to keep
beetles from migrating into new areas of the garden. Formulated
mixtures of the botanical insecticides pyrethrin or
azadirachtin may provide some control.
Spot treatments may be all that is necessary.