It's bad enough to have to swat flies all summer long. Now that the weather is turning colder, it seems like they are flocking to my home in mass! Where are they coming from and what can be done to stop their invasion?

Barb Ogg is an extension educator emeritus at the University of Nebraska. She says there are two kinds of flies that move in with you during the winter. One is a face fly and is very common in acreage settings. These flies overwinter as an adult, and feed on fresh animal manure. The other is a cluster fly, which is a parasite of earthworms. Both species have the same behavior: they search out the cracks and crevices of your home in the fall to hunker down.

"People that have flies in the middle of the wintertime have cracks around windows, or under siding, so that the flies are able to get into the structure, into the walls of the house," says Ogg. "And then, they sort of hibernate there for awhile as it cools off and then when we have these nice warm days in the wintertime, it’s warmer inside than it is outdoors, so they weave their way through the walls, through vents and things like that and then they show up inside."

Flies come out of their stupor and sluggishly walk around window sills and other openings. They're larger than common house flies and their movements are slower.  Since they are spending as much time airborne this time of year, fly strips are not as effective. But, because they are so sluggish, you may be able to easily whack them with a fly swatter or suck ‘em up with a vacuum. If you would prefer a less violent approach, try some of these gentler, more natural approaches.

Eliminate Food Sources

Try to see your house the way a fly sees it. Dirty dishes in the sink, unlidded trash cans, and compost bins, and half-empty pet food bowls are all inviting sources of food for flies. Go through your house room by room, and do what you need to do to shut down the buffet.

And, don't do just do it once in a while. To keep your home fly-free, get into the habit of doing a weekly (or bi-weekly) fly check, perhaps on trash collection day or when the maid is coming.

Clean Up After Your Pets

If you need a reason to stay on top of your pet-related chores, then here it is. Flies lay 75 to 150 eggs at a time, and they prefer to lay those eggs on poop. Becuase it takes as little as 24 hours for fly eggs to hatch, for every dog pile that you leave in your backyard today, you will be looking at 150 more flies tomorrow.

It's important to scoop up after your pets on a daily basis and be sure to keep their cages clean as well.

Figure Out How They're Getting In

It's normal for some flies to get in with the opening and closing of doors. However, if you have a lot of flies in your home, you need to figure out how they're getting in. Examine your window screens for tears, and patch or replace any that are damaged. Then, take a look at the caulking around all windows and doors. If you haven't re-caulked in a while, then that may be the culprit. Finally, inspect the weather stripping around your doors, and make the necessary adjustments or replacements to ensure your home is air-tight.

Use Plants to Keep Flies Away

If you want to go the natural route, flies have an adverse reaction to such herbs as lavender, mint, lemongrass, and basil. You can use them as foundation plantings around your house, or stick them in flower pots positioned by your front and back door.

Until Next Time...

Dick Gibb