Depending on the size of the opening, silicone caulk or expanding foam can help keep the bugs outside ... Use A Homemade Soap ...

Boxelder bugs affect outdoor and indoor spaces differently ... Diatomaceous earth is a natural, organic insecticide that can kill and prevent boxelder bugs from entering your home.

Depending on the size of the opening, silicone caulk or expanding foam can help keep the bugs outside. Boxelder bugs tend to hang out on sunny, south-facing walls. They're also attracted to light ...