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Strawberry
Root Weevil
Otiorhynchus
ovatus
Biology
Adult strawberry root weevils are brown-to-black, blunt-snouted weevils
that are about 1/3-inch long. The wing covers are marked by many rows
of small pits. Like the strawberry crown borer, the adult strawberry root
weevil cannot fly. Larvae are thick-bodied, white, comma-shaped, legless
grubs that reach approximately 1/4-inch in length.
The strawberry
root weevil overwinters as a full-grown larva, pupa, or adult in soil,
or as an adult in plant debris or other protective habitat. Larvae and
pupae complete development in the spring, emerging as adults in May or
June; overwintered adults become active in strawberries in May.
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Strawberry
root weevil.
Adult is about 1/3 inch (8 mm) long;
larva is about 1/4 inch (6 mm) long. |
Damage
Root weevil adults lay eggs in strawberries throughout the summer, with
each female depositing 150 to 200 eggs in the soil. Eggs hatch in about
10 days, and larvae burrow through the soil to feed on roots until they
mature or until cold temperatures cause a suspension of their activity.
Damage to roots and crowns caused by root weevil larvae can weaken, stunt,
or kill strawberry plants. Although adults eat notches from the edges
of leaves, their feeding causes no economic loss.
Control
The cultural practices described for the control of strawberry crown moth
also limit damage from strawberry root weevils, as flightless adults do
not easily reach new plantings if they are isolated from existing fields
and wooded overwintering sites. Where existing plantings are infested,
carbofuran (Furadan 4F) has been registered in Illinois under a 24©
label for root weevil control. Consult the most recent edition of the
Illinois Commercial Small Fruit and Grape Spray Guide for more information
on insecticides.
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