Why Do I Suddenly Have Large Flies in My House and How Do I Get Rid of Them?

Why Do Large Flies Suddenly Appear Indoors—And How Do I Get Rid of Them?

If you've suddenly got large, slow-moving black flies clustering on your windows, don't panic—but do take it seriously. In most cases, these are blow flies, and their sudden appearance usually means something has died somewhere nearby, typically a rodent or small animal inside a wall, crawl space, or attic. The flies hatch from pupae after feeding on the carcass and then start looking for a way out, which is why they're drawn to light and windows.

The good news is that in most cases, you won't need chemical treatment. Once all the pupae have hatched, the flies stop appearing on their own—usually within 7 to 10 days. In the meantime, open one window and pull the shades on the others so they fly out toward the light. A vacuum works well for removing clusters, and sticky fly traps on windows can help catch strays.

If the infestation is large, keeps coming back, or you're dealing with hundreds of flies over several weeks, you could be looking at cluster flies instead,a different problem that's best handled by a professional.

Professional Fly Control

At Gregory Pest Solutions, we've been helping homeowners and businesses deal with insects of all kinds since 1949. Whether it's a one-time fly problem or a recurring infestation you can't get to the bottom of, our licensed technicians can inspect your property, identify the source, and put a plan in place to fix it Get in touch with your local Gregory Pest Solutions team to schedule a free inspection today.