When you stop and think of all the things you bought last summer to help with flies it probably added up to real money and a lot of effort. And did it work well?

This year why not fix the problem at its source rather than just treat the symptoms. Try Fly Predators® brand beneficial insects.

They’re the safe, easy to use alternative to spraying gallons of pesticide, hanging dozens of stinky traps or putting up acres of sticky strips only to have the flies just keep coming back. And they keep coming back because all those things only affect the adult fly stage ignoring the 90% yet to emerge. So rather than doing what you did last year, and having the same fly problem this year, break the cycle with Fly Predators. You’ll have less flies for sure and probably spend less too.

My family started using Fly Predators 36 years ago with our horses and our fly problem literally disappeared. So we started offering them to others and over the past 35 years hundreds of thousands of horse owners have relied on them. The vast majority with great results as you can see from the quotes in this catalog.

Once someone tries Fly Predators for at least three shipments, most typically use them for as long as they have their animals. They really do work. You can see thousands of customer comments including those nearest to you by

Perhaps you’re skeptical that something as easy as sprinkling a small, inexpensive pouch of Fly Predators around your place every three to four weeks during warm weather could really work. You’re not alone, but last year tens of thousands of new customers ordered Fly Predators and most were delighted they "finally" tried them. This year why don’t you?

You see Fly Predators are perhaps nature’s original fly control. You almost certainly have some of the species that are included in our Fly Predator brand beneficial insects already working for you on your property. They’re part of the reason you aren’t literally knee deep in flies. You may have way too many flies, but without these good bugs, it would be far worse. By simply increasing the ratio of Fly Predators to pest flies, you can almost completely suppress the flies. There’s no downside as the Fly Predators do not bother either people or animals.

Fly Prevention: A Call Today Can Mean A Lot Less Swatting Later

An Ounce of Fly Prevention Starting in Spring is Worth a Pound of Cure Come Summer

The best way to control pest flies is to eliminate them before they ever emerge. By simply sprinkling a small bag of Fly Predators on your manure areas just as the weather turns warm you can prevent flies from ever becoming a nuisance. Then by continuing to release Fly Predators, on a regular basis through the warm months, you’ll continue to keep the fly population suppressed. Many of our customers say they hardly see a fly all season.

Quick and Easy To Use

Every three to four weeks spend a few minutes sprinkling Fly Predators near all areas where there is (or was) fresh manure or other rotting organic matter (spoiled hay, grass clippings). Just getting them close to these fly breeding areas is good enough as they self distribute up to 150 ft.

No Flies, No Pesticides No Larvicides, No Worry

Tired of endlessly spraying your horses with pesticides (and yourself while you’re at it) or concerned about feed through larvicides? Most horse sprays are repellents and only chase flies away for a short while... so they’ll be back. Using Fly Predators also completely avoids any of the potential adverse side effects associated with pesticides. Just reading the warning label on almost any fly spray is perhaps the best advertisement for biological control. By contrast there is no warning label for the species in Fly Predators and in almost 40 years of commercial use no known adverse effects.

A Great Value

Typically you need 1,000 Fly Predators per large animal every three to four weeks during warm months. With a cost ranging from $3.00 to under $2.00 per thousand, depending on monthly quantity, the cost per horse is minimal while the resulting benefits are substantial. For many, Fly Predators often cost less than all the other things they did before for flies.

Free Double Up Bonus

Our 35th Year of Satisfied Customers

For over three decades Spalding Labs has supplied Fly Predators brand beneficial insects to horse and livestock owners nationwide. Just try them for one season and you’ll likely use them as long as you have your animals. Once you get used to not having flies, it’s hard to put up with them again. That’s why more horse owners choose Spalding Fly Predators than any other biological control provider.

One call or easy online order is all it takes to schedule a full season of pay as you go shipments. If you need to cancel, you can do so at any time.

Just What Are Fly Predators

Fly Predators are nature’s own enemy of all common manure and rotting organic matter breeding pest flies, including the common house fly, horn fly, biting stable fly and lesser house fly. In the natural environment Fly Predators serve as a major check of pest fly populations by destroying the next generation of flies in their immature pupa (cocoon) stage.

Fly Predators are tiny, completely biteless and stingless. They never become a pest themselves. Because of their small size and the fact they live their entire life cycle on or near manure (where the pest fly pupa are typically found), Fly Predators go virtually unnoticed.

The current mixture of species marketed under the trade name Fly Predators include: Spalangia cameroni, Muscidifurax zaraptor, Trichomalopsis, Muscidifurax raptorellus and at times insignificant quantities of other fly parasitoid species. These species have been proven effective by both scientific tests and from decades of actual usage. There is no known method of fly control that offers 100% eradication of pest flies, Fly Predators do not totally eliminate the fly problem, they minimize it, but often dramatically.

The key is to maintain a sufficient Fly Predator population to stop each succeeding generation of pest flies. Because pest flies reproduce nine times faster adding supplemental Fly Predators every three to four weeks during warm months keeps the population balance necessary for good fly control. However, you must release enough Fly Predators to control all the fly reproduction in the area. You treat the farm not the horse. For example, if you board at a commercial stable, ordering Fly Predators for just your horse will not be sufficient as the flies that reproduce in the neighboring (within 1/4 mile) horses’ manure will easily reach your stall. Get the stable owner to use Fly Predators and then everyone’s horses will not be bothered by flies.

Proven Highly Effective For All Kinds of Animals

Application Tips: Easy and Quick To Use. Just Like Scattering Seeds.

Nothing could be easier. Just sprinkle Fly Predators out of their sealed see through shipping pouch near manure and other pest fly breeding areas. In a few minutes you’ve done your fly control for the month. Fly Predators ship in the immature stage, inside a pupa (cocoon) which looks like a black rice kernel. A few days after arrival they’ll begin to emerge and that’s when you release them. Fly Predators will not fly to, crawl on or otherwise bother you or your animals.

While Fly Predators stop pest flies from reproducing, they do not affect existing adult flies. So you can’t expect a fly free environment immediately following the first release if you start after flies are already present. Adult pest flies must either live out their short 21 day life span or be removed by supplemental methods of fly control compatible with Fly Predators. These include traps, sticky paper, or bait stations. Complete instructions are included with your first shipment including our handy 32-page Fly Control Guide.

Start Regular Releases Early

Keep in mind that it is much easier to prevent a buildup of pest flies than it is to get rid of them. The optimum time to start is when the daytime highs get into the 60’s. This is always before the flies are a problem. By starting prior to the first fly hatch there will be relatively few viable fly pupae that survived the winter so the ratio of Fly Predators to fly pupae is high. This allows the Fly Predators to reduce the initial fly breeding population to a very low level which can mean fewer flies all summer. Then continue with Fly Predator shipments every three to four weeks stopping a month before the temps drops down into the low 60’s.

If you start after the pest flies have built up to high levels, an initial shipment of two to three times the normal Fly Predator quantity will be needed to get control of the pest fly population as quickly as possible.

Helping Your Fly Predator Program

From the standpoint of fly control, the goal of good manure management is to minimize the available suitable breeding area. Flies need a moist medium to successfully reproduce, so spreading manure thinly to dry quickly helps. If it can’t be dried, putting it on a composting pile raises the temperature of all but the outer few inches too high for fly larva. For the same reason, if you’ve had much more rain than normal, then additional Fly Predators may be required for a few shipments.

Biology of Fly Predators

The Fly Predators did it again—No flies. With good manure management & daily cleaning we have enjoyed a fly free barn.

“The Fly Predators did it again—No flies. With good manure management & daily cleaning we have enjoyed a fly free barn. I own a veterinary hospital and feel I must have exceptional fly control and with your help I do.” Mary S. Los Gatos, CA

Fly Predators are what biologists call parasitoids. That is, they are classified somewhere between predators and parasites. Like parasites, Fly Predators are much smaller than their pest fly host. However, the effect the Fly Predators have on the pest fly's population is exactly like a predator in that the Fly Predators kill the immature pest flies.

Technically Fly Predators are tiny Hymenopteran insects of the Pteromalidae family, a family that contains many of the world's beneficial insects. These are pupal parasitoids as they attack the pest fly's pupa stage (the cocoon that houses the pest fly during its metamorphosis from larva to full-sized adult). Fly Predators are sometimes referred to as parasitic wasps, but unlike other Hymenopteran insects, such as bees, wasps and ants, Fly Predators are completely biteless and stingless.

Currently the mixture of species marketed under the trade name Fly Predators include: Spalangia cameroni, Muscidifurax zaraptor, Spalanagia endius, Muscidifurax raptorellus and at times insignificant quantities of other fly parasitoid species. This balanced mix of multiple strains and guaranteed yield from the most advanced quality control techniques means you can always count on the best results with Spalding Fly Predators.

A female Fly Predator shown on a fly pupa, ready to deposit her eggs in it. This kills the immature fly.

A female Fly Predator shown on a fly pupa, ready to deposit her eggs in it. This kills the immature fly.

Fly Predators never become a pest themselves. Being passive insects, they do not crawl all over you when being handled, nor will they migrate into living quarters as pest flies do. Since Fly Predators live their entire life cycle on or near the surface of manure and other decaying organic matter, and because they are so small in size, they go virtually unnoticed.

Fly Predators have improved our fly problem immensely. We own a black and white Clydesdale who is a fly magnet. He is very grateful for the relief.

“Fly Predators have improved our fly problem immensely. We own a black and white Clydesdale who is a fly magnet. He is very grateful for the relief.” Rebecca B. Bend, OR.

When they are released near fly breeding sites, the female Fly Predator searches through the area seeking out the fly's pupa. After locating one, she drills a hole in the pupal case, inserts her ovipositor, and deposits from one to a dozen eggs inside. After her eggs are deposited, she obtains nourishment by ingesting the fluids of the developing pest fly. The female Fly Predator then moves on and repeats the process until all her eggs have been deposited.

The Fly Predator's eggs that were deposited inside the pest fly pupa will develop into mature adults within 14 to 28 days. The pest fly larva is consumed as a source of food by the developing Fly Predators. Immediately upon emergence the Fly Predators mate and start the cycle all over again.

My life with my horses now in the summer time is wonderful. When I go somewhere else with no Fly Predators I know how good I've got it

“My life with my horses now in the summer time is wonderful. When I go somewhere else with no Fly Predators I know how good I've got it.” Laurin W. Brooksville, MS.

The life span of the female Fly Predator ranges from as little as two weeks to as long as one month. She will live just long enough to deposit all of her 50 to 100 eggs. When the pest fly's population is under control and only a few pest fly hosts are available, the female Fly Predator has the ability to reabsorb her eggs as a source of nourishment and thus is able to live up to a month while searching for pest fly pupae.

Fly Predators occur worldwide and in natural situations they are a major factor in the control of pest flies. However, where man has congregated domestic animals the presence of Fly Predators is often much rarer. One reason for this is that Fly Predators have not developed the immunity to pesticides that the pest fly has. One single application of pesticide or even the residue from previous pesticide treatments can completely eradicate the Fly Predators. The release of additional Fly Predators will help re-establish these native beneficials.

As there is no known method of fly control that offers 100% eradication of pest flies, Fly Predators do not totally eliminate the fly problem, they minimize it. Also, Fly Predators usually only disperse themselves 150 feet from where they have emerged, whereas pest flies migrate much farther, which means there will always be some pest flies coming in from neighboring uncontrolled breeding areas.

Put Fly Predators to Work For You This Year...

For 35 years, tens of thousands of horse owners have depended on Fly Predators. You can Too! Make this the year that you Kiss Flies Goodbye.

The Good Buy For Real Fly Free Relief