Box elder infestation
We have literally hundreds of box elder bugs in 2 apartment units where I work. We have a few in other units but these 2 two units are overrun with them. We have no trees within several hundred yards on one side and open fields on two other sides (no trees at all). I can't rent these units. We clean them out clean up the mess and the next day they are all over the walls and windowsills. What can I do? We set off bug bombs and it kills the ones that are climbing on the walls and inside but the next day it is the same mess.
Is there anything they would carry back to the nest and kill the nest?
Moffat County Colorado
Last year, due to the weather, there were an enormous number of boxelder bugs produced throughout Colorado. The warm winter with a heavy seed crop set things up. then, with the warm weather, at least two full generations were produced, allowing populations to build to their maximum.
Boxelder bugs can be managed best in a preventive manner, preventing entry into buildings when they move to buildings (usually beginning midSeptember and lasting until late October). Most entry into buildings is from the south and west sides. Every entry point must be sealed/caulked before they infiltrate behind walls.
Certain insecticide dusts, usually a desiccant dust such as Tri-Die, is sometimes injected into wall voids where insects aggregate for overwintering. Again, this needs to be done in late summer, before the insects move behind walls, and would completement the sealing/caulking.
At this point there is nothing to do but wait them out. They are behind the walls and will move about when there are warm days. Most will move outdoors, but some come indoors, causing the problem you have.
Bug bombs are worthless for this.
There is no nest. They are developing on boxelder and bigtoothed maples. Obviously these are some distance from your building, but apparently it is a very suitable site for overwintering boxelder bugs.
Sorry there is no simple solution. However, if there is some solace it is that they do not breed indoors and are not reproducing in the building. It is just that alot chose the wall voids of your building last fall as the place to wait out winter.