On the Fly

Not all small flies are the same. As a PMP, you know this all too well. And that’s why providing successful small fly control hinges on two important aspects: identifying the type of small fly and locating the breeding source.

While most PMPs reported fruit flies (41%) and drain flies (26%) as the species that accounted for most of their small fly service calls, PMPs also ran across phorid flies (19%) and fungus gnats (10%), according to the 2025 PCT State of the Small Fly Control Market survey. Bottom line? You have to be knowledgeable in all types of small flies.

“You have to have the correct identification before you can come up with a game plan,” said Zachary Hall, Thomas Pest Services, whose company offers training videos to help with continuing education on small flies, especially some of the species PMPs don’t see very often.

That game plan includes giving you clues on what areas to inspect and the kind of treatments that may be needed.

“Fruit flies and other flies like phorid flies are going to look similar, but you have to identify them first,” said Greg Bausch, American City Pest & Termite. “Often they’re going to breed in different places, and finding that breeding site is where you need to focus your treatment. Otherwise, you’re not really controlling the problem. You can do certain space treatments and things like that, but you’re just controlling adult fly populations, but not at the source.”

Finding the breeding source is vital to stopping small flies. But when it comes to locating the breeding source, the list of possible spots is long. You may feel like a detective investigating everything from drains, houseplants, beverage lines, mops or buckets. It can even be a structural issue, a broken pipe underneath a cement floor or a leak behind a counter.

Matt Henderson, Country Boy Pest Control, recalls one client who had a drain fly issue at her home. Even after Henderson treated all her drains the problem persisted.

“I started asking her more questions, taking my time to think about things to ask her. One question was: ‘When’s the last time you changed your toilet flanges?’” he said. “She hadn’t changed her toilet flanges in 25 years.”

Henderson suggested she contact a plumber as he suspected her flange was leaking — making it the perfect breeding ground for drain flies. “She called me back three days later. She said her toilet flange was leaking and the plumber replaced it,” said Henderson. “And they haven’t had an issue since.”

Even though small flies are tiny in stature, they can be a big headache for you and your clients. This can lead to continual or repeated services if you can’t determine the breeding source or if your client is uncooperative when it comes to sanitation issues. In fact, PMPs reported an average call back rate for small fly control jobs at 4.3%.

“If you don’t find the breeding source, you’re not going to truly control these insects,” said Dylan Blasingame, Blasingame Pest Management. “They breed so quickly. The main goal is to solve the problem. I tell customers all the time that sanitation is one of the key puzzle pieces through the whole control method. If you don’t cover all aspects of control, you’re not going to get control.”