School IPM Best Practices

Boxelder Bug, Boisea trivittata

Boxelder bug

Boxelder bug. Photo by William M. Ciesla, Forest Health Management International, Bugwood.org.

IPM Steps to Reduce Boxelder Bugs

1. Sample for Pest

Where to find it while inspecting: Often found congregating on sunny sides of buildings in the autumn and may use any entryway to gain access for winter hibernation. If you see one or two inside (away from obvious entries like outside doors) they may be entering living space from inside the wall.

2. Proper ID

Size and Particulars: Adults are 1/2", long, oval shaped, mostly black with bright red lines. Nymphs similar, but without wings.

3. Learn the Pest Biology

Life Cycle: Overwintering adults emerge from hibernation in spring, and females lay clusters of pale yellow eggs and aren’t particularly as to where. Eggs change to red and hatch within two weeks. Because there are generally two generations per year, you will find all types—adults, nymphs, and eggs—throughout the season.

Preferred Food Sources: First choice is boxelder, also maple and ash trees, occasional smaller shrubs. Nymphs eat both seeds and leaves.

Preferred Habitat: The bark of boxelder. Overwintering bugs will actively look for food sources inside on days when the sun warms the wall space. They will leave a strong odor if crushed and can also stain fabric.

4. Determine Threshold

Threshold: On warm spring or fall days, it is common to see boxelder bugs outside. A few may enter buildings through doors and windows. If you see more than a few inside throughout fall and winter, you may have a hibernation site inside wall spaces.

5. Choose Tactics

Best Management Practices: Remove female boxelder trees from areas near buildings. Exclude bugs from entering buildings by sealing all crevices.

Treatment Methods: Once they’ve gathered inside wall spaces to hibernate there is little you can do. In extreme cases of repeated infestation, a chemical treatment may be used outside along probable entry points, but this is a last effort that can be avoided by extreme care in sealing entry ways.

6. Evaluate

Was the tactic successful? Record the date pests were first noted, and the tactic you used, and its success. Use one of our RECORD KEEPING tools.

For More Information

University of Minnesota Extension: Boxelder Bugs

Penn State Entomology: Boxelder Bugs


When a pesticide application is necessary, all necessary and required precautions are taken to minimize risk to people and the environment and to minimize risk of pesticide resistance or pest resurgence. Pesticide use in your school may be prohibited or regulated by local policies or state and federal regulations. Risk reduction methods can include, but are not limited to, spot-treatment, the use of gel or paste bait formulations placed in inaccessible locations, injection into a crack or crevice, and other methods that reduce potential exposure.