Fly control is about more than simple fly spray. It’s a comprehensive and preventative approach to managing the fly population to the lowest tolerable level.
Whilst we’ll never be able to eliminate flies completely, there’s a lot we can do to keep them manageable and help our horses tolerate their presence.
But before we get started on the topic of fly control, it’s worth asking ourselves why we care about flies.
Why do we care about flies?
Flies are more than just a nuisance—they should be a serious concern for horse owners across South Africa. With our warm climate and long summers, flies thrive, causing discomfort, spreading disease, and even leading to infections such as summer sores and eye irritations.
Beyond disease, flies drain your horse’s energy and cause substantial physical and emotional stress for them. From being bitten hundreds of times a day to stamping their legs sometimes thousands of times a day and having flies sit in the corner of their eyes all summer, it’s easy to see why flies reduce our horse’s quality of life.
Types of fly
In South Africa, the most common flies affecting horses include:
- House flies (Musca domestica) – carriers of bacteria and irritants.
- Stable flies (Stomoxys calcitrans) – bloodsucking pests that cause painful bites.
- Bot flies (Gasterophilus spp.) – whose larvae burrow into a horse’s stomach lining, causing health issues.
- Horse flies (Tabanidae family) – aggressive blood feeders that stress horses and spread disease.
Feed through fly control
Feed-through fly control is not very common in South Africa but is widely used overseas. Also known as Insect Growth Regulators (IGRs), these products inhibit insects’ life cycles. In the US, for example, many IGRs are on the market that can be formulated into a feed or supplement and are safe for consumption.
IGRs don’t affect the horse’s body. They pass through the digestive system and end up in the manure, and from here, they prevent flies from going through their lifecycle and developing into flies.
The major downsides of these products are their low availability in South Africa and the requirement that all horses in a particular yard be on the product for it to be effective. It is not useful if fed to only two or three horses because that leaves a head of horses that are still actively cultivating the fly life cycle through their manure.
Fly predators
Fly predators are tiny insects that you release into the environment, and these predators stop the fly’s life cycle. Various species of fly predators are available. None of these predators is a nuisance to the horses or people. When sprinkled in areas where manure piles up, moisture pools or old hay breaks down, they actively seek out fly eggs and lay their eggs inside the cocoon intended to nurture the fly, thereby preventing the fly from reaching adulthood and halting the lifecycle.
The main downside of this option is that you must be very organised and keep on top of your orders. Skipping a month or introducing new predators late will disrupt control. In addition, the use of fly sprays is not advised in areas where these predators are used, as the fly sprays can inadvertently kill the predators, thereby nullifying their impact.
Companion animals
Chickens, guinea fowl, and swallows help control flies by eating larvae and adult insects. Having chickens around your barn can make a huge difference to fly populations!
Fly traps
Fly traps can be super helpful if used properly, but it all depends on an understanding of the kind of fly you are trying to trap. House flies make up the vast majority of flies in most horse barns. They don’t bite but are still very annoying to our horses. Stable flies, conversely, are biting flies and consume our horse’s blood. They look almost identical to house flies.
With the two looking so similar, it can be hard to tell the difference, but the best way is to look at the area of the body the fly is drawn to. House flies like sticky eye drainage and hang around on the face, whereas stable flies go for the blood in the legs and the underbelly.
If you have house flies, you can use odour traps or sticky traps. You generally need to add water to odour traps, and the unpleasant odour they produce attracts the house flies. Stable flies are, unfortunately, not attracted to either of these traps. Odour traps should be placed away from your barn to draw house flies away from your horse, and as house flies are quite sensitive to temperature, you should hang the traps in the sun in cooler weather and the shade in warmer weather. Sticky traps should be used inside your barn to collect the house flies close to your horse. Sticky traps should be hung at eye level or higher outside the stable, near some sunlight, and out of reach of curious horses.
Did you know?
House flies are attracted to the light, so most sticky traps are yellow and hanging them in sunlight can make them super effective.
Fly bait
Similarly to fly traps, fly bait attracts flies using pheromones (used to communicate between flies) and attractive scents to lure flies away from horses and poison them with insecticide. Fly bait must be housed securely in bait stations as it is also toxic to humans and other animals.
NOTE
There are sticky traps designed for stable flies, but we have not seen them yet in South Africa. These traps are made of light-reflecting material, which makes the trap emit heat. This attracts the biting stable fly because it assumes it is a mammal radiating body heat, typically a sign of a tasty blood meal. These traps need to be placed low because this is where the stable flies like to hang out.
Fly sprays
Most fly sprays contain topical repellants designed to repel biting insects. Some natural varieties are available for those concerned about chemical handling and use on horses, but they are of variable efficacy and should be used in conjunction with other methods for real impact.
Fly sprays can be applied directly to your horse or sprayed around the stables. Some residual sprays and products can be applied to stable walls and ceilings
Please always follow the manufacturer’s instructions for use.
NOTE
Even if your fly control is excellent at home, you will need fly spray for travelling or attending shows, so it is worth patch-testing your horse in advance to ensure they do not have sensitivity to the product.
Wearables
Fly sheets, fly masks, and fly boots fall into this category. Some horses dislike wearing these, but if your horse tolerates them, they provide excellent protection against biting insects. At HQ, we’re particular fans of fly boots, as they seem to dramatically reduce the amount of stomping our horses do in response to flies. This is very important for horses with thin soles, arthritis, etc., as every stomp sends concussive forces up the limb and can cause pain and exacerbate these existing issues.
NOTE
Fly sheets are not ideal at the height of summer as they can cause sweating and overheating.
Environmental management
This involves being strict about removing or eliminating areas that allow flies, mosquitos and ticks to proliferate. Fly eggs need moisture to hatch, so keeping manure heaps as far away as possible, keeping stables clean, being careful of pooling water, removing old piles of hay, etc., is very important in managing fly control. The final element of this is the use of fans; blowing a fan in the stable, particularly in the direction of your horse’s face, can help keep flies away as they struggle to battle the air current.
Conclusion
Fly control is an ongoing battle for South African horse owners, but with a combination of good stable management, protective gear, deterrents, and targeted fly-control products, it is possible to keep these pests at bay. Good luck out there!