June 8, 2020 
Most of us have probably come to accept that flies are a fact of life on the farm.
Sure, there are ways to combat them for a while, but it seems like no matter what we do, they just keep coming back. There’s one main reason for this: manure. After all, a fly’s specialty is to decompose rotting organic matter (yuck!).
Though no one approach can eliminate flies for good, a few years ago, I learned about a unique method of fly control called fly predators and had the opportunity to try them out in exchange for a review on my blog, but more on that in a minute…
To explain, fly predators consist of not one, but several different insect species including Muscidifurax raptorellus, Spalangia cameroni or Spalangia endius, and Muscidifurax zaraptor. These tiny insects feed on the larvae of the common house fly, horn fly, biting stable fly, and the lesser house fly.
What I love about fly predators is that they are a completely natural means of controlling the fly population, and these miniature fly killing machines are completely harmless to humans and animals. They don’t bite or sting, and they often go unnoticed because of their tiny size.
As stated above, I had the opportunity to try fly predators several years ago, and when I received my first shipment in early spring, I honestly had no idea of what to expect. Inside the small box, I found a plastic bag containing wood shavings, lots of small larva, and a few tiny black insects, which resembled gnats crawling about.
I remember thinking, So these are fly predators? They certainly didn’t look like they’d be capable of much destruction.
But I carefully read the instructions on the package and waited for more insects to hatch. Admittedly, I had no idea what I was doing that first time. I did know the fly predators needed to be released near manure, so I poured the insects and larva on top of piles around my pasture.
I was later told by a few people in the know that fly predators should not be placed on top of manure. The directions didn’t say this specifically, but the following month, I instead placed the fly predators near piles of manure or where piles had been before I picked them up.
I had high hopes for these little critters, but was still skeptical. I wanted to see all the flies around my farm immediately obliterated to smithereens.
Sadly, that did not happen. In time, as I continued to put out my monthly shipments of fly predators, I did witness a gradual decline in the fly population, but the flies never completely disappeared.
It’s possible that my positive results were hindered because we had record-breaking rainfall that spring, and wet conditions are optimal for fly reproduction. Not to mention, on at least two occasions, we received heavy rains the day after I had put my precious fly predators out.
But who knows…
I’m convinced that fly predators do work, but they definitely weren’t the miracle I was hoping for and I haven’t used them since that experience. That doesn’t mean I won’t try them again in the future, though.
Because flies and me, we’re still sworn enemies.
