Home-invading weevils

Strawberry root weevil (Otiorhynchus ovatus) is the most common home-invading weevil in Minnesota.

• You may find these weevils indoors from the end of June through August. 
• They are attracted to moisture and are often found in sinks, bathtubs, water basins and similar places.
• They are about 1/4 inch long, black or dark brown with rows of pits along their back.
• Strawberry root weevils do not fly.
• Sometimes people confuse strawberry root weevils for ticks. But, weevils have six legs and ticks have eight.
• The larvae feed on the roots of strawberries, evergreens—such as arborvitae, spruce and Japanese yew—raspberries and other brambles, grapes and many other plants.
• Adults start to emerge in early summer and feed on the edges of leaves.

Other weevils

Sciaphilis asperatus

• It is 1/5 inch long with a dark brown or black body covered with brownish or tannish scales.
• When these scales are rubbed off, the weevil appears brown with irregular blackish markings.
• Adults are seen from May into November.
• These weevils feed at night on the leaves of sugar and red maple, yellow birch, hazel and hophornbeam.
• The larvae feed on the roots of these plants, although they are not considered a pest.

Barypeithes pellucidus

• It is reddish brown and between 1/8 to 3/16 inch long.
• Not much is known about this weevil's habits, although it appears to feed on trees.
• Adults are common in June and July.

Imported longhorned weevil

Calomycterus setarius looks similar to Sciaphilus asperatus but is a little smaller. This weevil is found primarily in southern Minnesota.

• It is about 3/16 inch long.
• It has a dark-colored body covered with grayish-brown scales.
• Missing scales give the appearance of irregular black patches.
• Adults are present in homes in July and August.
• Larvae feed on the roots of aster, clover and turfgrass, while adults chew on the leaves of a variety of annuals and perennials.

Polydrusus weevil

Polydrusus impressifrons is common in the northeast and north-central areas of Minnesota in forested sites.

• It is a slender 1/4 inch weevil with a dark-colored body covered with lime green, or iridescent-looking scales (different colors are seen in different angles of light).
• Weevils often appear to be green with black patches when scales are missing.
• Adults chew the leaves of rose, strawberry, birch, poplar, willow and apple from June through August, while larvae feed on the roots of these trees.
• The feeding damage only affects the appearance of plants.

How to get rid of weevils

Keeping out weevils is the best control method

• Caulk cracks and ensure snug-fitting screens and doors to reduce the number of weevils that may enter a building.
• Weevils, especially strawberry root weevils, are attracted to moisture. You can trap them in shallow pans of water placed around the foundations or walls of the house.
• These pans do not capture enough weevils to reduce the number of weevils entering homes.

Weevils inside homes

• When weevils are found indoors, physically remove them with a vacuum or broom and dustpan.
• Pesticides are not effective or necessary.
• These weevils are harmless and temporary and will go away on their own.
• Their numbers can vary from year to year.
• If you see many weevils one year, it does not mean that they will be a problem again the next year.

Generally, pesticides are not required.

• When there are high numbers of weevils, you can apply a pesticide, such as permethrin or bifenthrin, around the home's foundation.
• Pesticides available to the public are not very effective against weevils.