Just about a month ago, I wrote about getting those houseplants back inside after vacationing in the backyard or on the patio. Now, there are other parts of nature that are trying to follow suit, but are really uninvited houseguests. This includes any kind of insect critter that has begun to look for a place to overwinter and wants to stay warm as long as possible.
One that you can count on every late summer and early fall is the boxelder bug. Easily identified by its red and black coloration, boxelders mass together on the warmer sides of our homes and while doing so, find their way in through cracks and crevices. Once inside, but without a food source, they will wander around using up the energy they have stored and leaving behind dark spots on walls and drapes. The vacuum cleaner is effective in capturing live ones and cleaning up the dead.
The notorious boxelder bug has some competition now – the brown marmorated stink bug, or BMSB. We have other stink bugs, as well, but this one is an import and moving quickly across all of the United States. Known to be from Asia, it was first confirmed in America in fall 2001 out East and is now found in many counties in Illinois, including Kendall, Kane and DuPage.
What makes BMSB different than all the others is that it feeds on many kinds of plants, both ornamental and food producing. Once established in an area, BMSB, in large numbers, damages both fruit and foliage of apple, cherry, peach and other trees. Perhaps the most unpleasant part of the BMSB is the smell emitted when disturbed, which is why they are called stink bugs.
Just like boxelder bugs, BMSB will gather in great numbers at the end of the summer, invading homes and outbuildings, seeking a suitable overwintering site. They will be sharing those spaces with others besides like Asian lady beetles and cluster flies.
The best protection is to keep them at bay and outside. Being sure windows and doors seal tight is the first line of defense. Many times the threshold seal on the door needs to be adjusted or replaced. Once inside your walls, they will continue to seek out heat and eventually make it into the home through wall outlets, light switches, ceiling fixtures, and openings around plumbing pipes. When you spot them, use the vacuum cleaner. If appropriate, an outside foundation spray also can help too. Look for the active ingredient deltamethrin, common in more than 30 available trade name products
By the way, if you have not started moving those houseplants inside, do not wait too much longer. Historically, we have had that first frost of the season as early as late September, and we are now well into October.
About the author: Richard Hentschel’s expertise extends across several subject areas with specialties in lawn care, fruit tree production, woody ornamentals, and home and community gardening. During his 45-year career in horticulture and agriculture, Hentschel became a well-known and respected expert for commercial and homeowner audiences, industry organizations, and media. He retired from University of Illinois Extension in April 2022 with nearly 30 years of service as a Horticulture Specialist and Educator in northern Illinois.