Fly control - Fly Eliminators/ fly predators

Its that time of year!
We have a small farm in a horse community. We are surrounded by other small private farms. Looking into options to help with flies.
We have a fly mist system for our barn but looking into other control options like fly predators.
Can you guys weigh in on if these systems have helped you? There are several variations/ sellers for these fly parasite programs. Are they all the same? One preferred over the other?

As an aside. For manure management we have a manure bin and have it emptied every 2-3mo when full. We do not spread manure on the property. We also pick manure from the fields every other day.

Aren’t fly mist systems a no-no with fly predators?


Correct. The fly mist system will kill the predators.

I have had very good luck with fly predators.

We had always used them and had very few flies.
When Covid hit and Mr. Trub lost his job, one of the things from the budget that went away was the fly predators.
Two summers with no predators made us realize just how much the predators had been doing.

We started up again last year, a little late, but they helped.

My experience is that Spalding has great customer service. Contact them and confirm if they would work in your situation or not. I think the fly mist system means they will not, but worth contacting them.

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I buy directly from Spalding and find they make a noticeable difference. It doesn’t eliminate them but the difference with and without is significant.

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I just read the Spalding information, and I have a question about my own barn situation would benefit from using them.

I do not use stall bedding at all. Horses are out 24/7 and come up to the barn at feeding time. They live on 5 acres. I pick the pasture manure daily and haul it to a community manure dump 3 miles away, so I really don’t have a specific manure area like the Spalding web site talks about as the place to deposit the predators.

Would fly predators be of any use for my place? The builder installed a fly misting system in my barn as part of the package but the only benefit I saw for misting was keeping the wasps and spiders away, but the wasps prey on larvae in the pastures including army worms so I quit using the mist several years ago.

I can say that I found Spalding to be honest. As in, telling a friend that they did not feel their product would be the best choice for them.
You might as well call them.

Do you take the manure every day to the dump site or does it sit in the field for a bit?

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if possible all of the neighbors need to be included in a joint plan of attack, all it takes is just one close neighbor to negate or limit your independent attempts

We are surrounded by empty land, the nearest other horse is now at least 3/4 mile away. We use both an overhead spray system that has nozzles in all areas of the barns plus on the exterior walls. Also use the fly predictors in the compost pile which is only used for wet bedding, all manure is deposed of offsite

This has mostly eliminated the flies

We still use fly masks for the horses, some with ears some without depends upon The horse.

Mostly once the temps get above 95 F the horses are put in their stalls to be under their fans

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Great insights
Will try giving Spalding a call tomorrow.
Was thinking of using them for our manure bin area and an area of the fields where the horses congregate. The misting system doesn’t hit those areas but good point!

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Misting the manure with pesticide will still effect predators.

I really only find them effective if I keep fly spray out of the stalls. I only spray the horses in the aisle or paddock.

Predators don’t fly far, so if you’re misting in the barn, and using predators way out in a pasture, you’re likely fine.

You can’t use feed-through IGRs, with predators in the same spaces, as the IGR will also kill the predators (by keeping the larva from being able to mature to adulthood)

I’ve used predators for years, starting a couple years after we moved here. They help a LOT, as long as you use enough of them, on a 3-4 week schedule depending on where you are, double up in the high fly months AND, you don’t have close neighbors who aren’t using anything

But if you’re picking manure every other day, I wouldn’t bother using anything but misting in stalls, and fly spray, otherwise you’re just removing all sources of predators and IGR chemicals

The manure bin isn’t a big source of flies, it’s going to be too hot too quickly

Wow that’s not been my experience at all. Most of my flies come from my pile. Sure, it’s hot inside, but flies breed in the top inch or along the edges where it’s not warm enough to cook them.

The Spalding site says “the primary fly breeding habitats in horse stables are those areas where manure builds up along fence lines (tough to clean up areas), and where manure is stored for later removal or handling. These are the primary fly breeding habitats and this is where you’ll find fly larva in large concentrations.”

I assumed manure was being put into a container that can be taken away, a large waste bin, which does get hotter, faster, than just a pile in the open.

If that’s not the case then yes, put the predators on that pile. I wouldn’t spend time putting them in the pasture.

I put manure from my stalls, into my compost pile behind the barn, which is “free range”, and I rarely see flies back there. I used to think it was just because there was rarely fresh manure back there because horses were in once a day, for an hour or so, but for the last almost 24 months there has been a regular addition to the pile several times a week due to horses being in for almost 2 hours twice a day, and I still don’t see flies back there. When I boarded, 15-30 stalls, where horses spend 20-22 hours a day, were cleaned 7 days a week, so a large pile was accumulated, taken away 2, maybe 3 times a year, and flies didn’t really exist there either. I don’t know what would be different about these 2 situations for there to be few to no flies. Maybe they are disturbed enough, new stuff added on top?

Maybe it’s regional/ climate dependent? I just ordered my predators “early” (and feel late to the game :roll_eyes:) after seeing all the flies in my manure pile that is behind the barn. I pick the paddock and stalls daily, and the horses are mostly in the paddock.

I swore they (Spalding) told me I could IGR with the predators - I just started the horses on Solitude today so I guess I’ll be giving Spalding a call to verify!

ETA: Called Spalding directly and they said IGR is okay to use with the predators!

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I use Spalding fly predators and Simplifly. If I use both I have good fly control. Last summer I quit the Simplifly early - thinking that the flies were under good control and maybe using it was overkill. That was a mistake as my fly population increased quickly and I never really got them under good control again until the end of the season.

I have read that barn misting systems just contribute to the flies becoming resistant - basically they are getting inoculated instead of killed. Also I don’t like the idea of the horses breathing that stuff constantly.


I don’t understand this at all. IGR works by inhibiting the formation of chitin, which is what makes the protective hard shell of all insects, including fly predators, and is what prevents larva from maturing into adults

We tried using the Fly Predators last year and can’t say we saw a real difference. Of course, we are surrounded by cows on both sides, so that’s probably why they weren’t very effective for us. I also pick out the sheds and around the barn twice a day (my horses live out 24/7 with access to shelters). The flies are honestly the worst out in the field, but I’m not sure there is anything I can do about that. I have decided to go back to Simplifly this year (I also thought you could not feed an IGR with the fly predators) and have invested in fly boots and masks for everyone. May try hanging some fly traps in the shelters to see if those help reduce the ones inside.

I’m also in an area with cows close by. And a swamp down the way. I didn’t find fly predators to be effective enough to warrant trying again. I’m considering trying Simplify or Solitude this year.

I use the disgusting fly traps and find hanging them adjacent to or near my horses preferred loafing areas to be somewhat helpful. Quikstrike bait scattered in and around the barn makes a noticeable dent too.

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There’s really no point in using predators or IGRs if you have close enough neighbors who aren’t doing any good manure control. Flies will just breed there and come bug your horses

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My closest neighbors with stock have an approximate ten acre pasture split into thirds and 3/4 cows on it. They do some rotation but no manure removal or dragging. They do mow some. The closet edge of their pasture is about 500’ from mine. Reckon I’d be wasting money trying an IGR?

from my experience only, I would expect there would be limited results unless every one is on some sort fly reduction program as a fly’s range can be 1 to 2 miles, some say up to 20 miles

also Flies can develop in soil that was soaked with water used to clean garbage cans, muck baskets and dumpsters.