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Why are Those Bugs Swarming Around My Front Door?

Julie Harris, Master Gardener

Why are Those Bugs Swarming Around My Front Door?

As the weather is growing cooler, you may be experiencing a mass of bugs swarming your outside walls and doors. As we get prepared for winter, the bugs that don’t die off, survive by burying themselves in the soil, or leaves. But there are a few who want very much to spend the winter inside your home. The “big three” offenders are boxelder bugs, Asian lady beetles, and brown marmorated stinkbugs. These bugs may not be noticeable in the summer when they live and feed on sources in your yard. As the weather grows cold, however, they look for ways to get into your warm house. They are especially drawn to the part of your house that gets afternoon sun.

Brown Marmorated Stink Bug

These bugs are most prolific during hot, dry summers following warm springs. This year may have produced the right conditions for them to be quite plentiful. In the fall, the bugs look for cracks and spaces around doors and windows to sneak into your house. While they are not generally harmful, they can be an annoyance. They don’t feed on wood or other building materials and they don’t spread disease to people or pets. However, Asian lady beetles sometimes bite when handled and they, along with the stinkbugs create a bad smell when stressed or crushed.

Asian Lady Beetles

The best way to manage these bugs is to seal cracks and holes around windows, doors and foundations. Check window screens, broken seals around doors and windows. Don’t forget to look at the seals around wires, pipes, vents, soffits and fascias. If you have large invasions, you can treat the outside of your home with an insecticide treatment although targeting these bugs is difficult. As they are not feeding while they are trying to invade your home, pesticides may not work. (Note that any use of pesticides must be done with utmost care as they carry some risk.) 


Once inside, your best option is to remove them with a vacuum or broom or just crushing them. Note that vacuuming won’t kill the bugs, so they should be disposed of outside. These bugs generally do not live for more than a few days inside your home when they are active but they can be a nuisance, staining surfaces with their excrement. Some bugs remain inactive in your home over the winter. If you see them inside in the spring, they are waking up and trying to go outside. They are generally slow moving and can be eliminated fairly easily.


In short, these bug invaders are big on the ICK scale but generally can be controlled without causing harm.



References:

https://extension.umn.edu/nuisance-insects/boxelder-bugs

https://extension.colostate.edu/topic-areas/insects/boxelder-bugs-5-522/

https://extension.umn.edu/yard-and-garden-news/temperatures-fall-home-invading-insects-come-knocking


Photo Credit: University of Minnesota Extension (1,3), University of Minnesota Extension, Susan Ellis, bugwood.org(2)

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