Why Do I Have More Indoor Pests in Winter?

By Chris Williams on January 7, 2015.
home in wintertime with snow at sunset

Pests like a cozy home in winter, too!

The answer to this question seems obvious to me. Why do we spend more time indoors in the winter? It’s cozy, dry…and warm. Pests like that, too. They’re perfectly happy staying outside when the weather is nice and there’s plenty of food. But when it’s miserable outside, pests look for warm, dry places to spend the winter. Actually, pests usually start looking for these places before winter even begins. Finding a place to spend the winter is a pest’s main job come early fall and cooler weather.

In fall, some insects that have only one generation a year (yellowjacket wasps, for example) die off, leaving only a few prospective queens to carry on next year. Other insects lay eggs in the fall before they die. These eggs will spend the winter and hatch in the spring. A large number of insects simply look for protected places to spend the winter and then become active again in the spring. Outside, these insects end up under bark, in old stumps, in firewood piles, under stones, in brick walls, in ground burrows — anyplace where they can get out of the elements.

Some of these insects, which we call fall invaders or overwintering insects, seem specially adapted to moving into our homes in the winter instead. This group includes stink bugs, lady beetles, cluster flies, seed bugs, certain wasps, boxelder bugs, and elm leaf beetles. Most of these insects feed on crops or trees outside and fly to buildings in the fall looking for openings to get inside. Once inside, they end up in attics, or in wall voids, or in cracks and crevices behind baseboards, etc. where they bide their time until spring.

Mice Want Inside, Too!

Besides overwintering insects, our homes are also invaded during the winter by mice. Mice can, and do, survive the winter outside in our region, but hey, if you can get into a nice warm house, why not? Most homeowners who never have mice indoors during summer months will discover that mice have moved in for the winter. If you don’t notice, or you fail to do anything about these winter mice, you will soon have many mice calling your place home!

You Can Keep Winter Pests Outdoors

You can keep these winter pests out of your home in the first place if you plan ahead:

  1. Make sure you have an exterior perimeter treatment of your home in late summer/early fall (see Get Ready for Fall-Invading Pests). Having Colonial Pest treat around the exterior foundation of your home will intercept and kill most overwintering insects before they can find an opening into your home (see Preventative Maintenance Program Keeps Pests Away Year Round).
  2. Make sure your home has been pest-proofed to keep insects and mice out (see How Do Mice Get into Houses?).  At Colonial Pest, we have trained technicians whose job is pest exclusion. They inspect your home and seal openings that insects and rodents can use to get inside. It’s a detailed job but they know how to do it and it’s permanent pest control (see Keep Fall Invaders Out!).

Photo credit: ungard / IWoman / CC BY-SA

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