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When will it end? That's what many Washington County residents are asking about the indoor presence of boxelder bugs.
Although bugs are present every year, they reproduced in such abundance last summer that people who had never seen them before reported masses of bright red nymphs in their yards and gardens by July. In autumn when the hordes of nymphs matured, many swarmed to the south walls of homes, entered through cracks, especially around doors and windows, and retreated to winter hiding places. Although mostly inactive in winter, bugs rouse frequently and show up in living areas.
Once the bugs have entered the house, vacuuming or sweeping is the only way to get rid of them. University of Minnesota Extension specialists do not recommend using insecticides to control them indoors. Chemicals can be used to reduce their numbers outdoors but it's usually less expensive and more effective to seal cracks and crevices so they can't get into the house.
Boxelder bugs feed mostly on the flowers and seeds of boxelder trees so they don't do much damage in yards and gardens. They don't bite or stink but they sometimes leave stains. Bugs emerging in later winter and spring will find an exit, die or disappear giving homeowners a break until fall when the cycle begins again. Fortunately, boxelder bugs usually aren't as abundant as they were this year. -Bob Bystrom, Master Gardener