Here are some ways to kill boxelder bugs outside:

1. Spray with soapy water: Mix a tablespoon of dish soap into a spray bottle of water. Spray the congregation of bugs until they disperse. The soap breaks down the bugs outer shells, so they dehydrate and die.

2. Use diatomaceous earth: Sprinkle food-grade diatomaceous earth around the base of your boxelder or maple trees. Then, scatter more powder around the perimeter of your home, being especially generous around doorways and windows. Diatomaceous earth is a natural, organic insecticide that can kill and prevent boxelder bugs from entering your home.

3. Use insecticide: Spray the outside of your home with insecticide if the bugs are swarming. Boxelder bugs release a chemical that attracts other boxelder bugs, which can sometimes lead to large swarms. This is especially common in the fall, when the bugs are trying to find somewhere warm to spend the winter. If a swarm occurs, use insecticide to kill the bugs.

Its important to note that when killing boxelder bugs, its best to avoid crushing them as they release an unpleasant odor. Instead, carefully scoop up and dispose of any bugs you’ve killed.