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Controlling Boxelder Bugs

Source: NDSU Extension Service Entomologist

Once the weather warms, boxelder bugs will begin to emerge from their hibernating places. If those hibernation sites include parts of your home, it is common for some to appear in living quarters. This is particularly true in early spring when outdoor temperatures are still colder than indoor temperatures. However, all feeding and reproduction occurs outside and any bugs that do find their way indoors in late summer or fall will become trapped and die or become dormant as cold weather arrives.

The adult boxelder bug is about 1/2 inch long and is bright red or black with narrow reddish lines on its back.

Spraying places where you see the bugs will only kill those you see and will not affect those still hiding in hibernation sites such as inside wall voids, attics, or under siding. Vacuuming bugs as they are seen indoors is effective and is less expensive and less messy than spraying.

The best time of year to attempt boxelder bug management is in the fall. As these insects prepare for hibernation, they will congregate on the sunny sides of buildings for warmth. At this time, a solution consisting of 2/3 cup of a detergent such as Tide or Dreft per gallon of water can be sprayed directly on the congregations of bugs. This will, however, only affect those bugs present at the time, and if another group forms at the later time, another application of the spray will be needed. Diazinon or Dursban applied according to label directions can be applied for outdoor treatment to reduce entry into the home.

In addition to exterior spraying in the fall, another preventive strategy involves sealing foundation cracks and other possible sites of entry. Attic vents can be screened over with conventional window screen. This will still allow air circulation but will prevent entry of boxelder bugs.

If you have further questions, please contact your county office of the NDSU Extension Service

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