If you keep seeing tiny flies running across the kitchen counter, the bathroom floor or the basement in your Hawthorne home, and they come back no matter how much you clean, you may have phorid flies. They're easy to mistake for fruit flies or drain flies, but they behave differently and they often point to a bigger problem. Phorid flies breed in decaying organic matter, and sometimes that material is somewhere you can't see, like a drain line or a broken pipe under the floor. Below, we'll cover how to recognize them, where they come from and how to track down the source. If you'd rather hand it off, our fly control team can find where they're breeding.
What Phorid Flies Are
Phorid flies are small flies, roughly the size of a fruit fly or smaller. They're tan, brown or blackish, and when you look at them from the side, the back has a distinct hump. That's why they're often called humpbacked flies. They're also called scuttle flies, because of the way they move.
Phorid flies lay their eggs on moist, decaying organic material. The larvae feed on it, then pupate nearby, and new adults emerge to start the cycle again. As long as the food source is there, the flies keep coming.
Signs You Have Phorid Flies
A few clues together usually point to phorid flies rather than another small fly.
- They run instead of fly. Phorid flies often scurry across counters, walls and floors in short, jerky bursts and only fly when disturbed.
- They hang around drains and floors. You'll see them near sinks, floor drains, toilets, basement slabs and trash areas.
- Cleaning doesn't stop them. You've tossed the fruit, emptied the trash and wiped everything down, and they're still there.
- There's a faint smell. A musty or sewer-like odor near a drain or in one area of a floor can be a sign of rotting material nearby.
Phorid Fly, Fruit Fly Or Drain Fly?
All three are small and show up in kitchens and bathrooms, but each one leads to a different source.
| Phorid Fly | Fruit Fly | Drain Fly | |
|---|---|---|---|
| Look | Humped back, tan or dark | Tan body, often red eyes | Fuzzy, moth-like wings |
| Movement | Runs in jerky bursts | Hovers around food | Short, weak hops |
| Breeds in | Decaying organic matter, drains, broken pipes | Ripe or fermenting fruit and liquids | Slime film inside drains |
For a closer look at the look-alikes, see our guide to fruit flies vs. drain flies vs. fungus gnats.
Why They Point To A Bigger Problem
Phorid flies can breed in ordinary places like a dirty drain, a forgotten bag of potatoes or a garbage can. Those are easy fixes. The harder cases are when the breeding material is hidden. A cracked or broken drain or sewer pipe under a slab or behind a wall can leak waste into the soil, and phorid flies breed in it and come up through gaps in the floor. They can also breed on a dead animal inside a wall or crawl space.
That's why phorid flies that won't go away deserve attention. The flies are the symptom. The real issue is whatever they're feeding on.
Phorid flies don't bite or sting. But because they breed in rotting material and sometimes sewage, they can pick up bacteria and carry it onto the counters, dishes and food they land on. That's reason enough not to ignore them in a kitchen, and a good reason to find the source quickly rather than just swatting the adults.
How To Find And Fix The Source
- Check the easy spots first. Look at garbage cans, recycling, pantry produce, pet food and any spills under appliances.
- Test your drains. Put clear tape over a drain opening overnight, sticky side down, leaving a small gap. Flies stuck to it in the morning tell you which drain is active.
- Clean drains mechanically. Scrub the drain and pipe walls with a stiff brush and an enzyme or bacterial drain cleaner. Pouring bleach down usually doesn't remove the buildup.
- Watch the floor. If flies come up from cracks in a basement slab or around a floor drain, there may be a leak below. A plumber can camera-inspect the line.
- Remove what you find. Contaminated soil or debris from a broken pipe has to be removed and the pipe repaired, or the flies will return.
When To Call A Professional
Call a pro when the flies keep coming after you've cleaned and tested every drain, when they seem to come up from the floor or when there's an odor you can't trace. EcoFusion technicians use Integrated Pest Management to find where flies are breeding, and our drain fly control service treats problem drains. If the source turns out to be a broken pipe, we'll tell you so you can bring in a plumber.
Phorid flies are small, but they're telling you something. Find what they're breeding in and remove it, and they disappear. If they keep running across your floors and counters in Hawthorne, EcoFusion Pest Control can inspect and help you find the source.