Ever since the removal of a large Manitoba maple in a nearby yard, we have been experiencing a massive infestation of box elder bugs. I’ve bought a high pressure hose to blast them away but is there anything else I can do? They are making it impossible to sit on our deck.
First, be assured that those Boxelder bugs (Boisea trivittata) will do no harm to your landscape. They are often present where there are box elders (also known as the Ash-leaf Maple, which may have been what was removed, not a Manitoba Maple) but usually not in large populations. However, in hot, dry weather, large swarms have been known to occur … and our weather this summer has been ideal.
Washing them away with a high pressure hose is a good solution. (Some people use a shop vacuum.) Insecticidal soap sprays will not be very effective since you must find and spray the host trees entirely.
Make sure you get them off your house and deck and look for cracks or openings where they might enter your home, since they are known to do so.