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Over the Garden Fence

Insects inside the home this fall

Late summer and early fall provide us opportunities to learn more about the insect world. With our outdoor bloom show coming to a close, there are a great many insects that had been feeding on flower parts that are now looking around for something else to eat or thinking about vacationing where it is warm – inside our homes.

Insects are really responding to the environment when you see them gather on the warmer surfaces of our home and later find their way clear inside; they simply are following the heat. These insects are not going to cause a problem indoors. In fact, without the right conditions for their survival, they will not survive but a few days to a few weeks inside, living off their stored energy from feeding outdoors.

When you examine these insects under a dissecting scope or hand lens, their mouth parts are pretty specialized, and they cannot just start to munch away on indoor plants, or get into our pantries and fabrics. (When we do have problems with our houseplants, it is because these are insects that came inside on the house plants when we brought them indoors and started multiplying without any natural predators to keep them in check.)

Spiders, earwigs, weevils of all sorts, crickets, Box Elder bugs, and a lot of hard-shelled beetles may have already or may soon start showing up. For the majority of insects, especially those that will not linger in the home, vacuuming them up or picking them up with toweling is often the simplest way to treat the problem. You often will find a collection of dead insects or insect parts in the corner of the room or in an out of the way place. This may be the work of a spider that is hiding out nearby. In nature, spiders are great predator insects.

All this insect traffic will subside once colder weather arrives, those insects will have found a place to overwinter outdoors. In those instances where a treatment is deemed necessary, use a product designed for outdoor use as a foundation spray around the home, focusing on those areas where an insect has easy access inside. (Always read and follow label instructions.) Insects like those cracks and crevices. Door sills, sliding glass door rails, where the garage door seals against the concrete, and where the siding meets the foundation wall are all places that insects will congregate. Other places to check are the caulking around the windows and doors, dryer vents, where the air conditioner lines go into the home, and where the water spigot comes out of the siding.

Sometimes we unknowingly help them out when we accidentally bring these insects inside in the last of the flowers we cut for display or when a dried flower arrangement is brought indoors for the kitchen table. Be careful; those dried flowers can give us additional trouble later in the form of pantry pests that may find a new home for the winter in our flour products.

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.