Flies Be Gone!

Well, it seems an appropriate time to talk about it since it won’t be long before “they” come and potentially make everyone’s life miserable on the farm. “They” of course are flies: house flies, stable flies, face flies, horn flies, heel flies, horse and deer flies. What they need that you have is nourishment to reproduce and to feed their young, namely blood for the adult females and manure for their kids, the maggots.  Of course, damp, rotting feedstuffs will do as well as manure. The “Good News” is that you have multiple options out there. You can attack the problem on several fronts. The “Bad News” is (also) that you have multiple options out there and in order to really reconcile the problem you need to attack the problem on multiple fronts.

I grew up in a household with a mother who viewed her kitchen like an FDA supervised gnotobiotic (germ free) lab rat facility. Even a single fly was hunted down as if there were a bounty on its corpse.  But it only took a 25 cent flyswatter in those days to restore a sense of safety and composure at home.

So, here are my suggestions to deal with our annual plague of an airborne livestock and human nuisance. It is a good idea to start with the prevention of the opportunism by making sure you reduce their habitat, also known as manure sanitation. Don’t let manure accumulate in the gutters, in calf hutches (especially clean daily! and add new bedding as shavings, saw dust, etc.) Stacked manure should ideally be moved ¼ mile from the stable if possible, since that seems to be their preferred maximum flying distance. Try to compost the manure; or at least stack it as a “fermented” pile. As you make the pile, add approximately 1/4-1/2 oz. daily per cow the following minerals (can add these in the stable): Gypsum, Dyna-min clay, Humates, and Zeolite. Cover the pile with soil or a plastic tarp to disallow adults to lay their eggs. The mineral additives eliminate the volatile gasses like ammonia, creating more nutrient-rich compost, and fewer gasses to attract flies. Liquid manure pits need to be “active” enough not to produce a crust, which is an ideal substrate for maggots. Spilled, rotting and wet feedstuffs, including unprotected round bales and bunker silage, are also opportune sites for fly reproduction. If this kind of feed is continually exposed, dusting regularly with Diatomaceous Earth would help as a deterrent.

Keep in mind that the life cycle in feed, silage bedding and manure is about 7 days. Allowing the substrate to be disturbed and to dry out is the key. Composted bedding systems in the barn are great if you stir the surface daily. Bottom line is that wet (50-70%) manure/feed/silage is what they need. Conversely, dry manure (50-70% DM) attracts beneficial mites which parasitize maggots. In field trials, mites reduced flies by 45-70% better than pesticides!

Other parasites are parasitical wasps (adults are the size of gnats), which are released beginning in April/May and then released weekly thereafter. Releasing their larvae around water troughs, manure piles, manure cleaner elevators, and group pens allows for very good coverage with encouraging results. (Spalding Fly Predators at Spalding labs.com)

Out in the pasture it would be ideal if you had an aggressive population of dung beetles or hogs/chickens to work over the cow pies, as they are a blinking billboard for adults to lay their eggs. This is especially true of biting face and horn flies. If you don’t have other critters to spread or bury the pats, you may want to drag the pastures to spread the pats and allow them to dry out.
Other wild friends you should have are birds like tree swallows!  I was on a farm (70 cows) that had 135 tree swallow boxes, providing two sets of fledglings per season. They estimated the birds consumed 500,000 insects every single day! They also had Pueblo swallows that built mud nests on the wayward side of the barn, as well as blue birds and barn swallows. These guys were aggressive, even eating leaf hoppers, horse and deer flies.

Now, to protect the stock when the pressure is high (wet, humid weather) consider Fly Repellents. Agri-Dynamics produces a very cost effective formula called Ecto-Phyte, which contains aromatic terpenoids in a solution that is both oil and water soluble. A mixture of 10% Ecto-Phyte, 5% mineral oil, and 85% water can be sprayed on livestock (avoid eyes!), and on walls, stanchions, etc. Some stockman use automatic applicators at the parlor exit door; for calves/heifers on pasture. An automatic mineral feeder apparatus (e.g. Protector) can be used which sprays the animal on the head, neck and shoulders each time it reaches in for salt/minerals. Adding oiler bags to this arrangement can provide even more thorough coverage. The surfactants and terpenoids actually “clean” the cows of manure and dirt, making them less attractive to flies. “Passive” mineral feeders that have a gravity flow wicking system that saturates a felt layer with the Ecto-Phyte mixture underneath the rubber lid that covers the mineral feeder are also worthwhile though they protect mostly the head area. Dusting cattle with finely ground white limestone (not hydrated lime) also acts as a repellent. Apparently, it works on a light reflection principle similar to “Surround” dust repellent on produce/fruits. You need approximately 1-3 lbs per cow/day, and you need good coverage.

A very inexpensive to build, yet effective, walk through trap can be made from plans available from the University of Missouri, Columbia. The plans available are identified as Plan 1-904-C-6 Fly Trap. It works by creating a dark tunnel effect, utilizing fans, water misters, chains, etc. to knock the flies off the cattle and forcing them into sticky tape, electric zappers, or one-way screens. The exit door contains plastic strips that remove the residual flies hanging on prior to the cattle going into the parlor/stable for milking.

“Mr. Sticky” type sticky tape is still a good idea to capture as many adults that are recreating in the stable. If you use attractant fly traps, stinky traps catch mostly house flies (as do electric light traps). The Olson Biting Fly Trap will attract stable and face flies and the house/deer flies are attracted to the Manitoba Trap.

So there you have it. Biological, botanical and mechanical controls that can create a balanced ecosystem on your farm where flies remain an incidental bottom of the food chain component that no longer create economic losses and misery for two and four legged residents trying to enjoy the sweet season of sunshine and fresh air.