I've found direct spraying of box-elder bugs with household-strength orange cleaner is effective in controlling them. This is (as all other treatments are) a contact agent only - i.e., it only kills the bugs that are sprayed directly. Once the soap solution dries, it is no longer effective. I use household-strength orange cleaner sprayed with a garden-sprayer attached to the garden hose. I spray the soap solution directly on the bugs crawling outside walls of the house, sidewalks, ground at the base of the tree, the tree trunk and lower branches, and their nests. To attract large numbers of bugs to a small area, I made a small, dense pile of box-elder branches, twigs, leaves and seeds near the base of the tree and left it for several weeks. This attracts thousands of nesting box-elder bugs, then I spray this heavily infested nest and throw away the treated debris. I sprayed several times a week during the summer to bring a fairly heavy infestation under control. I was careful to use as little spray as possible on the ground and protected nearby flowering plants, shrubs, bird-feeders, etc., from the spray.
This method is most effect when used with other methods of controlling the box-elder bugs (controlling nesting areas, keeping the tree base-area free of fallen seeds, leaves & branches, etc..).
