Strawberry Root Weevil: July's Accidental Invader

The strawberry root weevil is a very common insect found throughout Iowa. The shiny black, hard-shelled adult weevils are about one-third inch long. They have a pear- or light bulb-shaped body and long elbowed antennae. The wing covers are marked by many rows of small pits.

Strawberry root weevils emerge from the soil in mid-summer (July) after spending the past 11 months in the soil as larvae feeding on the roots of strawberry plants, evergreen trees and other plants. Root feeding by larvae is generally not significant as is the foliage feeding done by the adults.

Strawberry root weevils would go unnoticed except that large numbers regularly wander into houses by mistake as accidental invaders. They do not damage the house, the furnishings or occupants. They do not bite, sting or carry diseases to people or pets. They are a nuisance only by their presence.

Combating strawberry root weevils in the house can be difficult and frustrating. Prevent entry by sealing cracks and gaps in the foundation and around windows and doors through which the adults can crawl into the building. Spraying permethrin, cyhalothrin, cypermethrin or other residual landscape insecticide on and along the foundation and in outdoor areas of weevil abundance may reduce the number of weevils outside and thereby reduce the number wandering in. Unfortunately, spraying of large areas (10-foot perimeters up to the entire lawn) and frequent reapplication may be required.

Adults already inside need only be vacuumed or swept up and discarded. Household aerosol insecticides are not very effective for controlling these weevils.

Strawberry Root Weevil

Strawberry Root Weevil


Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Yard and Garden, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on July 11, 2007. The information contained within may not be the most current and accurate depending on when it is accessed.