Strawberry root weevils are brown or black insects with leathery wings. Adult strawberry root weevils eat the leaves of strawberry plants, leaving notches along the edges. In larvae form, they are white or cream with no legs. Strawberry root weevils, which reduce plant vigour and eventually kill plants, also wander into your home at the end of summer and become a nuisance. You can use several methods to kill strawberry root weevils.
Confirm the presence of strawberry root weevils by inspecting your plants for notches on leaf edges left by adult weevils. At night, check your plants with a flashlight to spot them from plant leaves because they only feed at night.
Fill a plastic cup with a mixture of 1 tbsp of detergent and 1 cup of water. Dig a hole in areas with weevil damage and set the cup in it until the lip is flush with the ground. This acts as a trap and will kill a small number of strawberry root weevils, according to Cornell University.
Spray affected plants with an insecticide containing either bifenthrin or malathion as the active ingredient. For best results, apply the treatment at night when the adults are active, about two weeks from the first sign of strawberry root weevils feeding on your plants.
Use a vacuum cleaner to remove strawberry root weevils inside the home. Generally, chemical treatment is ineffective indoors because the weevils are usually scattered in various areas.
Spray a residual insecticide on the outside of your home to prevent strawberry root weevils from entering. Use an insecticide that contains carbaryl, diazinon, malathion or chlorpyrifos on the sides of the building and around the foundation, doorways and windows. Repeat treatment every three weeks, if necessary.