Dairy Fly Parasites
Guaranteed Live
Fly Parasites are silent but deadly to flies.
Harmless to the Environment
Shipments on a Weekly Schedule


  • Do they work? Definitely! When the fly parasite hatches the female must seek food and reproduce. To do so she seeks out fly pupa, stings them and lays eggs in them. This process kills the developing fly. The female fly parasite will sting multiple fly pupa killing each one. The eggs she lays will develop and hatch helping in your fly control. By constantly releasing fly parasites during the summer and through fly parasite reproduction, your farm can achieve significant control of your premises greatly reducing the fly nuisance.
  • How well do they work? All dairies large or small will benefit from them. How well they work depends:
    Are they supplied in adequate numbers for the full season-weekly during the peak season and are they used in conjunction with good manure and feed management?
  • Are they cost effective? Many dairies see fly parasites as a profit center to increase milk production
  • How do they work? They are a nocturnal beneficial insect that will canvass your dairy seeking their only food source fly larva (eggs). They burrow down in the manure and silently kill the fly pupa.
  • What about safely? Dairies use insecticides, feed through products, chemical sprays and poisons. All these products come with complex warning labels for your cows or people administering these poisons. Fly Parasites have no warning label. They are safe to use around all livestock, vegetation and humans.
  • Where do you disperse them? Flies breed in semi moist manure, feed areas and around the inner and outer edges of your barns. If you have flies, it is almost certain they are breeding on your farm and not coming from the neighbors. Disperse where you think fly development could be happening then the fly parasites will canvass and go to work. It is important to disperse them throughout all areas so fly outbreaks do not occur.
  • How many should I use and how often? We provide guidelines on usage based on how many cows you have. Count all the cows including calves. Often calf areas are heavy breeding areas. If you want stronger control purchase at a higher count level based on the guidelines. Extra fly parasites means better control.
  • How do I know they work? Fly parasites do not affect existing flies but as you sleep the fly parasites will be working the dairy killing larva and as time passes you will wake up with fewer flies each day. Cedar traps, Electronic Zappers and Fly Tapes will not harm the parasites and are good effective products to reduce existing adult fly population.
  • Can fly parasites be used with chemical fly sprays or other fly control methods? Yes. If you spray chemicals on the parasites you will kill them. If you have a spray program, release the parasites a couple of days after you have sprayed.
  • How do we put them out? Shipments are delivered on a regular basis. Most dairies appoint one person to disperse them - often the owner. Spread them throughout the dairy in the evening - like dispersing grass seed. The fly parasites will soon hatch and start working. Unlike other fly control, fly parasites are not limited by location. They will canvass your dairy seeking fly larva wherever it develops inside or outside. When putting them outside it is best to cover them up with manure, sand, dirt, hay so they are protected from the sun and birds until they hatch. Once hatched they will be under the surface and safely working.