Case Studies

Pests We Treat Case Studies: Yucky drain attracts Phorid flies - Pest control project in West Windsor

Monday, February 6th, 2017 by Christopher Morgan


One of my larger residential accounts is a 55+ community in West Windsor, where I perform a weekly commercial service. The property manager informed me that one of the residents had complained of small bugs invading her kitchen. 

I was familiar with this particular unit because this resident had a problem with Phorid flies in the past. Phorid fly larvae require decaying organic matter to survive, so drains are an ideal breeding environment since they are often coated with organic material and standing water is usually present. The top photo shows why drains are the perfect harborage for Phorid flies.

Fruit flies and drain flies also commonly breed in drains. All of these flies are small “gnats,” so it’s easy to confuse them. Pest control technicians distinguish Phorid flies by their humpbacked appearance (in fact, these bugs are often called humpback flies), and their peculiar behavior of rapidly running across counter tops, tables, and windows. Although these bugs can fly, their flight is short and erratic.



Although I had treated this home before, it was apparent that these pesky flies were breeding deep in the drains. This time around I din’t want to take any chances. This Phorid fly infestation needed to be resolved for good. This time, I asked the maintenance crew unscrew all the drain covers in the kitchen in order to give me good access to apply the products that would get rid of these bugs.

I applied three different types of bio sanitizer down the drains. A common DIY mistake is trying to use bleach and hot water to kill these drain-breeding bugs. It just doesn’t work. You must use a bio sanitizer to dissolve the underlying organic matter that fly larvae need to grow. I first applied a hot spot liquid containing enzymes mixed with water to break down the food materials coating the drains. Next, I applied thicker bio gel to continue breaking down the organic material over time. Finally, I applied a bio foam sanitizer to further break down any stubborn grease build-up in the drains. 

With this trio of bio sanitizers, any Phorid fly larvae lurking deep the the drains will be destroyed, and I’m confident that the kitchen will soon be bug-free. No one likes to see bugs in their kitchen, especially when they are flying out of kitchen drains like cars exiting the Lincoln tunnel during rush hour!