Health risk
As well as being highly irritating to horse and rider, they also cause difficult behaviour as your horse tries to escape them. Flies also present a health risk as vectors of disease and infections can quickly spread through a yard where flies will go from horse to horse. Fly strike is possible from eggs laid on open wounds then hatching into maggots.
The reality is, once you need to start using fly repellents, there are already flies breeding at your yard.Fly control using fly predators tackles flies at the source before they become a problem. Fly predators are tiny beneficial insects, harmless and nuisance-free to all animals and the environment, yet they are highly effective at controlling flies in equestrian environments by killing them in their developing stages.