Fly parasites are a natural enemy of flies. Their whole purpose in life is to source out pupating flies to lay their eggs. The parasitic wasp will hatch out, consume the pupating fly and then hatch out themselves only to repeat this scenario again and again thus breaking up the life cycle of the flies.

Parasitic wasps are already present but not in high enough numbers to control areas that already have fly problems. They are tiny critters that do not target or harm humans or livestock.

They do not fly long distances, but instead flit around the area where they are released so it is important to release them appropriately.

They are a safe and effective method to control filth-breeding flies.

Parasite Release

Your parasites arrive as inoculated fly pupae. They are in various stages of development. When you see the tiny wasps it is time to populate the areas where flies are breeding. Ensure you populate the entire area where the flies are breeding but ensure they are placed in areas where the livestock will not be walking. Release around the edges of bedding and feeding areas, along fencelines and where vegetation is decomposing. Ensure you do not place your biologicals in areas that will be in full sun or in areas where liquids accumulate. If you are releasing them in full sun areas lightly kick a bit of bedding over the area where they will be released. They will continue to hatch over the next couple of weeks.

Other Considerations

Only flies that breed in filth will be controlled — house flies, stable flies, manure flies, flesh flies, blow flies, etc, so basically, most flies! It is best to also set up traps for adult flies, especially if you already are seeing flies. The life cycle of the flies is often a bit shorter than that of the parasitic wasps so a multifaceted method of control will show better results.

If you release the correct amount of parasitic wasps when you just see flies beginning to appear and your enterprise is relatively clean, then one release of the parasitic wasps is often enough to see good control of the flies.

Releasing biologicals later in the season or when fly problems are already out of control will necessitate multiple releases in order to gain control of the fly population. However, once you have gained control of the fly population, then each summer you can reduce the amount of parasitic wasps released to a bare minimum while still having good control of the fly population.

Biological control is not for everyone as it is not an instant fix of a pest problem. However, the long term result is almost no filth-fly population. Please note that flies not breeding in filth may increase but they cannot be controlled with this method as they breed on the animals themselves.

It is important to evaluate each enterprise as an individual from the perspective of fly control using parasitic wasps. Consideration of the fly population, the area of the enterprise, the manure management and the willingness to set and manage adult fly traps are some of the criteria we use for evaluation in determining the number of flies present.