Fly control: tags, pour-ons, and the manure problem underneath

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Research. We have not been through a fly season here yet. This is what the categories are, what each costs per head across a season, and the failure modes not printed on the packaging. Once we have run a summer and know what our own pressure looks like, this page gets updated with the date.

Most of what gets spent on fly control is chemistry bought to solve a manure problem.

Name the fly first

The control that works depends on which fly you have, and they are not the same animal.

Horn flies stay on the animal nearly all the time and breed in fresh pats out on pasture. They sit in a mass across backs and shoulders.

Face flies feed at the eyes and nose and also breed in pats, but spend most of the day off the animal — so on-animal products do less about them.

Stable and house flies breed in wet rotting matter: spoiled bedding, spilled feed, the mud ring where the round bale sat. They bite at the legs. They come out of your barnyard, not your pasture.

Go and look at where the flies are sitting before you buy anything.

Manure is the lever

One pat can produce hundreds of flies. The wasted hay and mud around a bale ring is the largest fly nursery most small places own, and fixing it is free.

1. Move the feeding site. Not once a year — every few weeks through winter, so no one spot becomes a permanent bed of wet hay. 2. Handle bedding properly. A wet pile beside the barn is a hatchery. Composted so it heats through, or spread thin, it is not. 3. Rest and drag pasture. Breaking pats up dries them out; rotation does much the same. That needs temporary fence, and temporary fence needs a charger that holds up in tall summer grass — there is a page on that.

Skip this and buy chemistry instead, and you will be buying it again next year, and the year after.

Cost per head, per season

• Insecticide ear tags — $2 to $5 a tag, commonly two per head. Call it $4 to $10 a head, plus two handlings: one to put them in, one to take them out.
• Pour-ons — $1 to $3 an application, repeated through the season. The total depends on how many times you go through, which is the number nobody prints.
• Dust bags, oilers, back rubbers — $40 to $150 for the unit plus charge; per head it gets cheap fast even on a small herd. The catch is siting. Hung somewhere optional, a fraction of the herd uses it. Hung where they must pass under it to reach water, most do.
• Feed-through in mineral — a few cents a head a day, so $3 to $15 a season. Only affects what breeds in the manure of animals eating it, and only if each eats a consistent amount. With cattle over the fence next door, that ceiling is low.
• Traps — sticky ribbons for pennies, jug and bag traps $8 to $30 plus bait. Worth having around the barn. Close to pointless against horn flies, which live on the animal.

Why tags stop working

Two reasons, both ours rather than the tag's.

The class, not the brand. Tags come in a handful of insecticide families — pyrethroids, organophosphates, a few others. Pyrethroids have been used heavily for decades and resistance in horn fly populations is widespread. Swapping one pyrethroid brand for another is not a rotation. The class is on the label; the shelf tag will not tell you.

Leaving them in. A tag releases at a falling rate. Left in past the season it puts out a small amount for weeks, which is exactly the condition that selects for flies able to shrug it off. Pulling tags is a second round-up plenty of people skip. If you will not do the pulling, do not tag.

Going in too early is the same problem in reverse — the tag is spent before peak pressure arrives. Ask your vet or extension office what threshold applies here.

What this page does not cover

Nothing here is a claim about animal health. Flies and disease is a veterinary subject; take it to your vet. Zero flies is also not reachable — chasing the last ten percent costs more than it is worth.

What we are buying

Fly pressure is local and we have not seen ours. Moving where the hay goes down is not one of the options — by this page's own argument it is the groundwork, it costs nothing but the walking, and it happens whatever else does. What is open is what gets added on top of it, and that cannot be honestly chosen until a summer here has shown what the pressure actually is and how much of it the moving takes out.

Whatever we buy goes in this section when we buy it: what it was, the insecticide class off the label if we tagged, and what it came to per head. The Research tag is a season's work, not a purchase. It changes when a summer is behind us and we can say what our own pressure looked like, whether the tags came out on time, and how much of the difference came from the hay moving rather than the chemistry.

Before you buy

• Name the fly first. On-animal products do very little about barnyard flies.
• Cost the labour, not just the product. Two handlings is the real price of tags.
• If you tag, write the pull date on the calendar the same day you put them in.

— Chris D., McEwen, Tennessee