November 4, 2005 | By: Terri McLean

With the cool, crisp days of autumn at hand, a group of insects and spiders have begun their search for a warm, cozy place to settle for the winter. Chances are they’re headed for your house.

“Several kinds of spiders, beetles and flies spend the winter as adults in some protected place,” said Lee Townsend, entomologist with the University of Kentucky Cooperative Extension Service. 

Often, these harmless but annoying fall invaders find shelter behind the bark or in the cavity of a tree. But just as often, they will find a house or other structure to call home during the winter months. 

“They crawl deep into cracks and crevices,” Townsend said. “If these lead them indoors, it is warm enough for them to stay active during most of the winter.”

One of the most common intruders is the Asian lady beetle, or ladybug. These insects begin their movement into buildings about mid-October and continue through mid-November, Townsend said. They usually enter through dark openings, especially beneath exterior siding, around window and door frames, soffits and fascia boards, and through attic and crawl space vents.

The good news is that their entry into houses and buildings usually is a short-term event, Townsend said. If they do invade, the best way to remove them is with a vacuum cleaner.

Spiders are also frequent intruders, and this fall has been a busy one for these eight-legged creatures. Most spiders, including the common wolf spider, are the wandering type and do not have toxic bites like the brown recluse or black widow, Townsend said. 

However, their scary image makes spiders particularly unwelcome guests. “Most of our associations with them are generally not good,” he said.

Flies, such as the face fly, can also enter houses in large numbers during this time of year. They are more likely to invade houses in the country or near cattle herds.

Although most of Kentucky’s fall invaders are harmless – some are even beneficial – they can be a nuisance. That’s why Townsend encourages people to take action before the fall invaders get indoors.

“Once they get inside your options are limited,” he said. 

The best course of action is to deny insects, spiders and other pests entry, a procedure known as pest-proofing, Townsend said. This includes taking many of the same steps homeowners take to winterize their houses – installing door sweeps or thresholds at the base of all doors, sealing utility openings where pipes and wires enter a house through the foundation and siding, and caulking cracks around windows and doors. It also includes repairing gaps and tears in window and door screens, and installing wire mesh over attic, roof and crawl space vents.

While pest-proofing can be labor intensive, Townsend said it has proven effective and can eliminate the need to use insecticides. 

“We try to discourage insecticides and use some of the physical controls,” he said, adding that the commonly used total-release aerosol products, or “bug bombs,” are not as effective and can be dangerous if not properly used.

However, if necessary, pest-proofing can be supplemented by an exterior treatment with an insecticide to help keep pests out. Longer-lasting liquid formulations containing synthetic pyrethroids are recommended.

No matter which course of action you take, Townsend said it’s important to identify the intruder first. County Extension offices around the state can help. 

“Once you know what it is and know a little bit about it, it generally sets your mind at ease and helps you make a good decision about what to do,” he said.


Writer: Terri McLean 859-257-4736, ext. 276

Contact: Lee Townsend, 859-257-7455