Strawberry Root Weevil

strawberry root weevils are about one-quarter inch long, shiny black and light-bulb-shaped.
Strawberry Root Weevils.  Photo by Kim Axne.

Description of strawberry root weevils 

The strawberry root weevil (Otiorhynchus ovatus) is a very common insect found throughout Iowa. The  shiny black, hard-shelled adult weevils develop from larvae that live in the soil and feed on the roots of strawberry plants, evergreen trees and shrubs. In mid-summer, the adults emerge from the soil. They feed on plant foliage but cause no significant damage to the plants. They would go unnoticed except that large numbers regularly crawl into houses by mistake as "accidental invaders." They are harmless and do not damage the house or furnishings. They do not harm people or pets, and are a nuisance only by their presence.

Strawberry root weevils have a distinctive "light bulb shaped" and rather long, elbowed antennae. They are approximately 3/16 inch long (5 mm).

Management of strawberry root weevils 

Some of the invasion by strawberry root weevils and other accidental invaders can be prevented by exclusion techniques that close their routes of entry. Look for and seal cracks and gaps in the foundation and around windows and doors through which the adults can crawl into the building. Spraying a residual 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. For more information on insecticides please see this article.

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

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 September 13, 2016. The information contained within may not be the most current and accurate depending on when it is accessed.