Quick facts
- Weevils are small beetles that have noticeable snouts.
- They are often lightbulb- or pear-shaped.
- The immature, legless, grub-like larvae feed on plants.
- Adult weevils look for shelter in unfavorable weather conditions, especially when it is hot and dry.
- Weevils enter buildings by crawling through cracks or openings around foundations, doors and windows.
- They do not harm people or pets, or damage buildings or property, or infest food products.
- They are a temporary nuisance.
How to get rid of home invading 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 foundations or walls of the house.
- These pans do not capture enough weevils to reduce the number of weevils entering homes.
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.
CAUTION: Mention of a pesticide or use of a pesticide label is for educational purposes only. Always follow the pesticide label directions attached to the pesticide container you are using. Remember, the label is the law.
Weevils inside homes
- When weevils are found indoors, physically remove them with a vacuum or broom and dust pan.
- 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.
Types of weevils
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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.
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 seems to be 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 - 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.
The 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.
- This weevil 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.
The 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 irridescent-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 during June through August, while larvae feed on the roots of these trees.
- The feeding damage only affects the appearance of plants.
Reviewed in 2019