Tracing the roots of a phorid fly invasion – Pest Administration Skilled


Writer’s Observe: This month, as an alternative of answering a reader’s query, I’m sharing how we helped troubleshoot a home-owner’s very powerful phorid fly account this summer season. I enlisted the assistance of all the Rollins technical crew with this one: Glen Ramsey, Ben Hottel and particularly Frank Meek, BCE, who investigated in particular person.


The life cycle of a phorid fly. PHOTO: COURTESY OF, AND COPYRIGHTED BY, GENE WHITE, [email protected]

For functions of this column, let’s name the house owner Jim. He and his spouse have lived in a home in Northwest Georgia for greater than seven years, and started having a phorid fly problem about three years in the past. Jim studies “1000’s” of phorid flies are caught in hotter climate, however not less than it calms down in winter. In summer season, nonetheless, they’ve to make use of lids on their cups, for instance, simply to drink their morning espresso. Jim despatched us a number of pictures to show this was a severe state of affairs.

The house is crawlspace building, with a metropolis sewer line. In response to Jim, two different homes to the east of his residence have points with phorid flies; the home to the west doesn’t.

Jim went via the litany of what he had accomplished earlier than reaching out to us:

  • His pest management service inspected for sources a number of occasions and didn’t discover any. For the file, he wasn’t utilizing a Rollins agency.
  • His pest management service handled the drains a number of occasions with a foaming enzymatic cleaner, to no impact.
  • He had his sewer line and different pipes inspected by a plumber with a digital camera, who confirmed there have been no breaks.
  • He contacted town to conduct a smoke take a look at on the sewer line operating to the home, to make sure the plumber’s inspection didn’t miss any leaks, and to confirm no sewer gasoline was venting into the house. No points had been discovered.
  • He consulted his native college extension service, to substantiate the insect identification.


To troubleshoot this phorid fly problem, we first regarded on Google Earth to see what was surrounding Jim’s property. By our estimation, this can be a “regular” subdivision. All of the properties regarded pretty new — lower than 20 years previous and possibly a lot youthful. Jim says his home was in-built late 2007 and completed in early 2008.

The realm did have some agriculture close by that would trigger phorid fly points, however the prevailing winds weren’t from that route. There was a landfill that’s now shut down, but it surely wasn’t very shut, and the prevailing winds weren’t from that route.

We adopted up with Jim about whether or not there may very well be an previous septic tank, or maybe the realm was constructed atop an previous cemetery, and so on. He mentioned he was not conscious of any such elements that would play a task. We teasingly requested whether or not he suspected any neighbors of burying individuals within the yard, and whereas he laughed at our joke, he did admit he suspected one home’s sanitation practices had been less than par and may very well be a potential supply.


The Rollins Technical Providers crew mentioned the state of affairs and determined we weren’t going to get any additional with no bodily inspection. We had been underneath journey restrictions in June, however happily, Jim’s residence was only a day’s drive from our Atlanta, Ga., headquarters. Frank volunteered to test it out.

Frank made it clear to Jim that this was a courtesy go to, and that we had no expectation of signing him to an account. Fairly, we supplied to develop an answer, if we may, after which let him determine whether or not he wished to do it himself or rent a pest management firm (any firm). Frank’s inspection netted the next:

  • Giant numbers of lifeless phorid flies and stay phorid fly exercise had been famous all through the inside of the house.
  • No breeding websites had been discovered anyplace within the residing area or crawlspace.
  • Exterior, within the northeast nook, there have been indicators of phorid fly breeding present in decaying mulch that was overshadowed by overgrown shrubs.
  • A number of exterior entry factors had been discovered that may very well be exploited by phorids to enter the construction.
  • Relating to the encircling property, Jim revealed the problem started when a brand new proprietor moved in subsequent door (northeast facet). He says the neighbor doesn’t use trash service, accumulates trash over a interval of weeks/months, then removes all of it in a rental field truck, normally late at evening.

Frank gave Jim 5 particular suggestions:

  • Seal gaps on exterior and round basis vents.
  • Deal with entry factors and resting surfaces with pesticides.
  • Take away and exchange mulch, and skinny shrubs and different landscaping to reduce the buildup of moisture within the mulch.
  • Place traps within the mulch mattress to behave as interceptors from the neighbor’s home.
  • Rent a pest administration agency to particularly deal with resting surfaces for phorid flies.


Jim mentioned following Frank’s suggestions resulted in a dramatic lower in stay fly sightings, though the inhabitants was nonetheless energetic all through the summer season. Then one sizzling day in August, the neighbor opened her storage door a number of occasions over a interval of some hours— leading to actually 1000’s of flies in and round Jim’s home.

Jim known as the County Code Enforcement Workplace to file a criticism, and his different neighbors did the identical.

A number of days later, a Code Enforcement inspector drove out, however was denied entry into the neighbor’s residence for inspection. He instructed the neighbor she had seven days to scrub up the trash or face penalties. The neighbor denied having greater than two baggage of trash within the storage.

But the next morning, at 3:40 a.m., Jim noticed the neighbor hauling a number of trash baggage out to a 15-foot rented field truck.

We adopted up in early September, and Jim reported the issue primarily was resolved.


  • At all times positively determine the pest. This directs you the place to look.
  • At all times examine all the pieces, even areas you don’t suppose could be a problem. Phorids breeding open air in mulch in a middle-class, suburban neighborhood are uncommon, however that was the state of affairs on this case.
  • As a pest administration skilled, by no means stick your nostril in a battle with the neighbor. Let the house owner take the lead. Have info; don’t make assumptions or blindly imagine what you’re being instructed by the house owner. Checking the interceptor fly entice ranges, even after the moisture problem in that space was resolved, was fairly telling.
  • Belief your information and coverings. If the widespread breeding websites have been recognized and handled, however the problem stays, step outdoors the field. Ask your self, the place are they proper now? Exploring all angles solved the case.