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Fly Parasite Industries

Dairy & Feedlots

Here are a few tips for more effective fly control around dairies and cattle operations.

Use Fly Parasites

The good news is that flies can be managed just like you manage every other element of your operation and we believe that using Fly Parasites for fly control can increase you profits (due to increased productivity) much more that the cost of the program. Furthermore, important but not financial benefits of using Fly Parasites include the health concerns of using chemical pesticides and a generally more pleasant environment to work and live in.

a. Identify the Problem

One of the first steps is to identify the type of flies that are causing the problems. Houseflies, cluster flies and face flies all typically swarm around the head of the animals and these flies breed mainly in manure. If you notice swarms of flies around the legs of the cows that are biting and the animals are kicking, these are probably stable flies. Biting flies normally breed in composting material including rotting vegetation, manure and animal feeds. If you notice flies attached to the back of the animals, especially when they return from pastures, these probably are horn flies. Horn flies breed mainly in fresh cow patties in the pastures and Fly Parasites should be released in these areas for effective control.

b. Start Early in the Spring with Scheduled Releases

It is much easier and more cost effective to prevent a build up in the fly population than to try and control an established problem. The best time in the spring to start your fly control program is when you notice flies on the south side of the barns AND when the chance of heavy frost has passed. For all dairy and cattle operations, it is recommended that scheduled releases of Fly Parasites are on a two week interval. This is because in Canada, the developmental cycle (egg to adult) of most flies is about two weeks, and this schedule will provide effective control. Releases of Fly Parasites should continue until the first frost in the fall or when flies are no longer a problem.

c. Release an Adequate Number of Fly Parasites

The number of Fly Parasites that need to be released for effective fly control varies from farm to farm depending on sanitation practices, the normal weather patterns and where the animals are kept (confined or in pastures). A starting point for a typical shed dairy would be about 500 Fly Parasites per animal every two weeks. This would have to increase slightly for pasture or organic dairies and decrease for feedlots. We at Goodbugs.ca will recommend a customized program for your operation.

d. How and Where to Release Fly Parasites

Just open the package of Fly Parasites and sprinkle in areas you have identified may be high fly breeding areas. These places may include:

  1. Calf areas-typically this is the worst area for flies. Two factors contribute to the high number of flies. First the calves are fed milk, which produces very rich and moist manure; perfect for fly reproduction. Second, fresh straw or sawdust bedding is just added on top of old bedding and the warm moist environment of the old bedding promotes fly production.
  2. Along the fence or paddock lines where the cows, heifers or cattle are kept
  3. Adjacent to feed or watering areas (especially for biting flies)
  4. Along fence lines if pastures are to be treated (especially for horn flies)

Manure Management

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. Once you have decided how best handle your manure, you will be able to identify areas of your operation where most of the fly reproduction is occurring, and will be able to effectively attack your fly problem.

a. Good Sanitation

Removal of manure and decomposing feed from the paddocks, sheds, calf areas, and feed aprons is the single most effective operation that will reduce fly populations. Once removed from these areas, decisions must be made on what to do with the manure.

b. Remove the Manure from the Site

Hauling manure during the warmer months every two weeks is an excellent option. The manure should be taken at least 800 meters (or 1/2 mile) from the paddocks. In most Canadian regions, the majority of flies take about two weeks to develop from egg to adult, however this time can be shorter if there are very warm conditions (+ 25 C). 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.

c. Pile in one Location

An effective method of reducing fly reproduction is to pile all the manure in one location. The single pile will reduce surface area for the flies to breed and he heat generated within the manure pile is too hot for flies to survive except for the top 15-20 cm (6-8 inches). It is interesting to note that Fly Parasites have adapted to burrow about 15-20 cm into manure searching for fly pupae. Many farmers have found that covering a manure pile with black plastic increases the temperature within the pile and reduces the surface area available for flies to land on (and breed).

d. Spreading Manure

Flies require a moisture content of 35-70% to reproduce. If you are in an area that has prolonged dry spells, spreading your manure thinly over the fields and pastures is another option. The danger with this option is that if it rains before the manure dries, you are increasing the surface area for flies to breed. Many farmers wait until the cooler months when flies are not a problem to spread their manure.

e. Lagoons or Settling Ponds

Many dairy and cattle operations separate solids from liquids and the liquids are held in lagoons. Fly larvae cannot reproduce in liquids, however where the moisture content is below 70% will be areas of fly reproduction. This can be along the edges of the lagoons or if a solid cap is allowed to form over the pond. Some operations aerate their lagoons to prevent a cap from forming.

Use of Fly Traps, Sticky Tapes, or Fly Baits

Fly Parasites will effectively kill developing flies, however they do not attack adult flies. Whether these adults originated from your farm or if they migrated to your farm, the effect is the same; they will bother the livestock and lay eggs. If you reduce the adults, you reduce the number of eggs laid and the Fly Parasites will more effectively attack the developing flies.

Fly traps, fly baits and sticky tapes (and some contact sprays that are used on ceilings and walls) are all excellent methods to knock down adult flies. Fly Parasites are not attracted to any of the baits, traps or tapes, however we do not recommend aerosol or fogging chemical sprays as these will have a detrimental effect on the Fly Parasites.


We strongly recommend using a method that targets adult flies as part of your fly control program.

Please contact us for a NO OBLIGATION discussion on a customized fly control program (1-888-668-7264). We are not after a fast sell, but rather we hope to have a long-term satisfied customer.

Our business has grown across Canada virtually by word of mouth and we welcome all inquiries. Our commitment to you is to create the BEST, MOST ECONOMICAL AND LONG-TERM BIOLOGICAL FLY CONTROL PROGRAM.

Fly Parasite Industries

The majority of flies in and around Canadian farms can be controlled using a Fly Parasites program. Below is a list of the most common industries that utilize Fly Parasite programs.