General Sanitation

It sounds simple but overall sanitation is the most important and effective way to control flies. If you had no fly breeding sites you would have no flies developing at your facility.

But what’s the chance of that with cows? Slim to none. So the best choice is to do the 20% of the work that will make 80% of the difference and let Fly Predators take care of the rest.

Flies Are Delicate?

Believe it or not flies are hard to raise. The insectaries that produce our Fly Predators have to raise billions of flies to provide the hosts. And there are plenty of ways to screw up a batch of flies. Flies are very sensitive to moisture, temperature and diet. We strive to optimize their reproduction, you should strive to do the opposite. Its not hard if you know their vulnerabilities.

Manure Management

For most commercial livestock operations manure management is THE most important variable in any fly control program simply because this is the largest single source of (from a flys perspective) "the good stuff". But be aware that some biting flies reproduce in rotting vegetation, not manure, so see the next section.

There are two variables with manure that you can most easily change. The first is the quantity of manure, the second is the moisture content of that manure.

Move It

Hauling manure at least a 1/4 mile away in the summer no less often than every seven days is one option. This distance and time is important as flies generally travel no more than 1/4 mile (they can go farther) and they take at least 8 days to go from an egg to an adult fly at summertime temperatures. If you are going to spread it nearer, then do that in the cool months when flies are not a problem.

If frequent hauling is not practical, then take advantage of the other things you can control about manure, the moisture or to a lesser extent the temperature.

Sink It

Flies cannot reproduce underwater so holding manure in a lagoon and keeping the solid cap mimimized can make a huge difference.
Flies cannot reproduce underwater so holding manure in a lagoon and keeping the solid cap mimimized can make a huge difference.

A fly larvae has to be in a medium that is between 40-60% moisture or it simply wont complete its development. Increase the moisture of your manure by holding it in a liquid lagoon as a fly cant reproduce underwater. But make sure that you do not let a solid cap form on that lagoon or you will have a huge fly factory there. The top of the cap will be too dry and the bottom next to the water will be too wet, but somewhere in the middle will be just the perfect moisture for optimum fly production. Not Good.

The cost of diesel to agitate it regularly or adding enzymes to help keep it liquid can be a great investments in fly control.

Concentrating manure into piles reduces the available fly breeding areas as the middle of the pile is too hot.
Concentrating manure into piles reduces the available fly breeding areas as the middle of the pile is too hot. Spread Fly Predators with a small cup to better control how much goes where.

Pile It

In areas that receive regular summer rains, one alternative to a lagoon is to collect the manure frequently and stockpile it in a pile. When you do this the manure that is deeper than six inches from the surface becomes too hot for a fly larvae to survive due to decomposition. So even if the pile is mountainous only the outer surface will reproduce flies. One big pile is better than a bunch of small piles as you are trying to minimize the surface area. If necessary, cover the pile with black plastic to increase decomposition.

For the best fly control, do not water the pile and disturb it as little as possible until fly season is over unless you can "till" it on a weekly basis.

Dry It

Clean barns can mean dramatically fewer flies and the minimum number of Fly Predators needed for optimum fly control.
Clean barns can mean dramatically fewer flies and the minimum number of Fly Predators needed for optimum fly control.

For areas that receive little moisture during the summer a good choice is to dry the manure. Best is daily collection of fresh manure and spreading it thinly on crop and grassland areas. Running a harrow or screen drag around your pens and pastures to break up the pats into smaller faster drying pieces can be very effective.

Keep in mind that you are in a race with the flies as you want that manure to be less than 40% moisture by the 5th day from new or when it came out of the lagoon. This is because at the optimum temperature of approximately 85°F it takes at least 5 days for a pest fly to pupate (form its cocoon) which is a really critical time for the moisture level. If its drier than 40%, the flys puparium (cocoon) doesn't form properly and that particular fly is toast.

Keep in mind that you are in a race with the flies as you want that manure to be less than 40% moisture by the 5th day from new or when it came out of the lagoon. This is because at the optimum temperature of approximately 85°F it takes at least 5 days for a pest fly to pupate (form its cocoon) which is a really critical time for the moisture level. If it’s drier than 40%, the fly’s puparium (cocoon) doesn’t form properly and that particular fly is toast.

temperature of approximately 85°F it takes at least 5 days for a pest fly to pupate (form its cocoon) which is a really critical time for the moisture level. If it’s drier than 40%, the fly’s puparium (cocoon) doesn’t form properly and that particular fly is toast.

Calf barns are a prime
Calf barns are a prime "hotspot". Remove manure and wet bedding frequently.

Clean It

Do the best you can to clean stalls, corrals, paddocks, pens, drainage areas, loafing sheds, calf barns, feeding aprons, spilled feed and other decaying organic matter at no more than a seven day interval to minimize fly breeding. It doesnt take much material to reproduce a lot of flies. Daily pickup is preferred, but if you remove those pupae before the flies have emerged, (8 days minimum) the difference can be enormous.

Find Your Fly Hot Spots

Fly Larvae (Maggots) are your early warning sign that more flies are on the way in a week or so. If you see more than normal number of maggots react quickly. Remove the manure or add more Fly Predators.
Fly Larvae (Maggots) are your early warning sign that more flies are on the way in a week or so. If you see more than normal number of maggots react quickly. Remove the manure or add more Fly Predators.

At many facilities we visited where flies were a problem we often would find one or two locations that likely were producing the majority (maybe 80%) of the flies. These were locations where the manure was kept at the optimum moisture content for maximum fly reproduction. By simply focusing on these areas first you can make the biggest fly reduction for the least cost and effort. Fortunately these areas are easy to find, look for extra wet spots. It"s easy to confirm their fly production levels by noticing how many larvae (maggots) are in that material.

Worst offenders can be calf barns where new bedding is simply placed over old bedding rather than old wet bedding being removed. While it might look dry on top, dig down a few inches and you"ll find the gooiest, messiest, most perfect fly factory around. Combine that with the richer diet calves get and you"re creating a 4 star gourmet fly attraction.

But other less obvious areas that may not seem to have a lot of flies can still be the location where flies reproduce. That little ponding by a ramp, the dripping faucet by a water trough, the spoiled feed in a round bale feeder.

Check potential fly breeding hot spots regularly. They can be your early warning allowing you to stop a pest fly infestation before it gets out of hand.
Check potential fly breeding hot spots regularly. They can be your early warning allowing you to stop a pest fly infestation before it gets out of hand.

Give Flies the Boot

If you suspect a fly breeding hot spot, take a stick or your boot and dig down a few inches and see how many maggots are there. See a few no big deal, see dozens or a hundred and you"ve hit the spot. Beside cleaning up here, or if you can"t clean this up, put Fly Predators within 50-75 ft. Wherever you see a maggot, in a week or so you will have a fly pupae there, which is the stage the Fly Predators attack.

Fly Larvae (Maggots) are your early warning sign that more flies are on the way in a week or so. If you see more than normal number of maggots react quickly. Remove the manure or add more Fly Predators.
Fly Larvae (Maggots) are your early warning sign that more flies are on the way in a week or so. If you see more than normal number of maggots react quickly. Remove the manure or add more Fly Predators.

Consider the maggots your early warning sign for flies. Every week when you release Fly Predators, do the kick test and see what you"ve got for maggots at each location where there is moist manure. If you suddenly see more maggots in one area, put more Fly Predators there. If you suddenly see more maggots everywhere, perhaps due to the weather, then call and have us send more Fly Predators as you"ve got more flies coming in the next week or so. You can move around your bonus 50% extra shipments at no additional cost.

The extra Fly Predators won"t stop the extra flies that emerge before they get there, but they will stop the buildup that would otherwise be following.

Biting Fly Breeding Areas

Flies can only reproduce if they have the right moisture level. The manure on the top is too dry, on the bottom it’s too wet, but in the middle there’s an area that’s “just right” at 40 - 60% moisture.
Flies can only reproduce if they have the right moisture level. The manure on the top is too dry, on the bottom it’s too wet, but in the middle there’s an area that’s “just right” at 40 - 60% moisture. Finding these hot spots and removing them or adding Fly Predators close by will make a huge difference.

Unlike the House Fly that breeds principally in manure at livestock facilities, the Biting Stable Fly breeds in areas with spoiled feed. This can include the bottom of piled forage, round bale feeders, storage bunkers or simply the material that missed the feed bunk. If its gotten wet and been sitting there a while, better check it. Spread this material to dry or remove it and be sure to place some of your Fly Predators near here.

More Rain = More Flies

If you have more rain than normal you will likely see more flies. Since pest fly eggs and larvae need to be in a moist medium, if it"s wetter than normal more breeding areas will stay just perfect for producing lots of flies.

Flies have a staggering reproduction potential with each female fly laying up to 900 eggs. Thankfully due to natural predation (from beneficials like Fly Predators, beetles, Mites, ants, birds, etc.) plus the need for a moist environment for development, only 2-4% of fly eggs generally make it to adults.

But a small favorable change to factors affecting their survival rate, like more rain (or decimating the beneficials with pesticides) can mean a huge increase in the numbers of flies. This is one of the reasons why there are "good" and "bad" fly years. Also, it only takes one burst of wet weather, in an otherwise dry year, to yield a larger than normal hatch of flies who then can hang around for nearly a month.

If do you have a rainy spell, by reacting quickly and stopping the extra reproduction before the fly population builds up, it will take less effort and cost than waiting until the flies are intolerable.

Flies rest in weeds. Keeping it mowed “encourages” them to go elsewhere.
Flies rest in weeds. Keeping it mowed “encourages” them to go elsewhere.

Weed Control

Surprising as it may seem, flies need a place to rest and get out of the heat or cool temperature. Weeds and tall grasses are perfect for this so if you remove weeds from around buildings you can "encourage" pest flies to hang out elsewhere.

Attractant Traps

There are innumerable different traps available on the market. The key point to understand is that there are different traps for different species of flies. There is no one trap that catches all species.

Most of the traps sold in feed, farm and hardware stores are for House Flies as they are the most common pest fly. Many can have an effective attracting radius of about 100-150 feet. Your farm store is a good resource for the traps that work in your area.

Trap placement is important. If the farm has a small or moderate fly problem, traps placed close to the home or in the barn can attract flies from all over the area and make the problem worse. It is better to set the traps close to fly breeding sites with any prevailing breeze blowing from the trap toward the breeding area.

Traps should be placed near or on the ground and in sunny areas if you are in a moderate climate. If there is grass or weeds put the traps just above that. Don’t put traps in shady, dark or cool areas unless your temperatures are above 95-1000F. Attractant traps will not catch Fly Predators or other beneficials as they are not attracted by what is irresistible to a House Fly.

Sticky Fly Traps and Tapes

Farnam EZ Trap™
Farnam EZ Trap™

Most Sticky Fly Traps, tapes and paper, unlike Attractant Traps, can be hung in barns as they do not draw house flies from afar. Old fashioned fly paper or sticky coils are cheap but are not as effective as newer Sticky Traps such as the Farnam EZ Trap. Roll-up reels of sticky tape offer larger surface area and are easy to “refresh” by just cranking. Again if putting a Sticky Trap in a barn locate them in areas with sunlight, not in dark areas and down low. The exception would be when placing them directly over your cows in a milk parlor or walkway.

Stable Fly Traps

Farnam Bite-Free Stable Trap™
Farnam Bite-Free Stable Trap™

If you have flies that look like House Flies but bite like the dickens or your cows are kicking off the milkers you have Stable Flies. If you want to catch these you need Stable Fly traps. Fly Predators will control Stable Flies, but you need to put them where Stable Flies reproduce.

Farnam offers the Bite-Free Stable Fly Trap™ which is available in feed stores. Unlike House Fly traps which use smell to attract the flies, Stable Fly traps attract their target by visual means. So place these traps at least 10ft. outside of your barn, in sunny areas, where they can be seen by the flies. Stable Flies stay near the ground so put traps low, not more than 4ft. high. If you need to put them in pastures set them every 50-100ft. in places where your animals can’t mess with them. They’re not poisonous, just very sticky.

Poison Fly Baits

If you are not adverse to using poison fly baits, they can be effective and are a far preferred alternative to area aerosol pesticide spraying when using Fly Predators.

This is because the attractants in fly bait do not interest either Fly Predators or any of the other beneficials whereas most sprays are indiscriminate and kill all the Manitoba Trap good beneficials more effectively than the pest flies. This will make your fly problem worse in a few weeks. Normally baits will only be needed to quickly reduce an existing House Fly population if starting a beneficial program late, or if extra control is needed for an outbreak of adult flies due to weather or other temporary factors.

Your vet, local feed store or county ag advisor is the best source of information for what baits are effective now in your area. Understand that flies quickly develop pesticide resistance so "old favorites" may not be as effective as newer products. ALWAYS read and carefully follow the instructions.

Other Beneficials You Want to Encourage

Dung Beetles

"Dung beetle" is the common name for beetles that are members of the Scarabaeidae family These beetles breed, feed, and tunnel in dung deposited on pastures.

"Dung beetle" is the common name for beetles that are members of the Scarabaeidae family. These beetles breed, feed, and tunnel in dung deposited on pastures. (You have them if you see many “holes” in your cow pats). Through their activities, these beetles break up and bury the dung pat. This dries up the pat and removes it as a breeding site for pest flies. Hence, Dung Beetles are most efficient in reducing numbers of flies if the beetles disperse and bury the dung within a few days of its deposition before the flies can finish their development. Dung Beetles have been known to reduce Horn Fly and internal parasite populations by more than 90%.

Dung Beetle populations can be decimated by the toxicity of manure from Dung Beetle populations can be decimated by the toxicity of manure from the use of some de-wormers. So if you have Dung Beetles select a de-wormer that offers lower toxicity to beetles and other beneficials such as Fort Dodge’s Cydectin.

Mites

Tiny Mites ( 1/32" or less in length) are found practically everywhere, including the breeding sites of the Stable Fly and House Fly. Predaceous Mites, such as those in the family Macrochelidae, can be important natural enemies of these pest species. By feeding on eggs and young maggots, one Mite can kill up to 36 House Flies per day. In field studies, calf pen manure and outdoor piles of dairy cattle manure produced up to 67% and up to 45% fewer House Flies, respectively, when Mites were present than did adjacent areas where Mites were killed with the application of pesticides.

Mites are among the first predators to colonize manure because they disperse by phoresy; i.e., they

Mites are among the first predators to colonize manure because they disperse by phoresy; i.e., they "hitch-hike" on other insects. Hence, flies arriving to lay eggs in new breeding sites also may be carrying predacious Mites that will feed on these eggs.

Mites can be best used by conserving their natural populations with the following practices: keep manure dry with good ventilation and good drainage. This will promote the growth of Mite populations, which prefer manure with a moisture content of 50-70%.

Leave behind a a small residue of old manure when cleaning out barns, to provide a source of Mites to colonize the fresh manure. Avoid the use of larvicides unless their effects are known to be limited to the pest flies.


What Others Are Saying
Diane P
“ I have been very happy with the results from Fly Predators. I've been using them for three years and will continue to use them. ”
Diane P
Spartanburg, South Carolina
Don't Put Up With Flies! Get Fly Predators!
Fly Control for Dairy Sections
Dairy Guide to Fly Control Sections
Dairy Literature (PDF)
BBB Online
©2010 Spalding Laboratories