Comments and opinion by James I. Sprague, Nutritionis

Cleaning manure in the late winter and early spring before the flies hatch is important. This includes pastures where hay was fed on the ground.

Stable Flies at the Ranch or Farm
Stable flies breed in a mixture of manure with hay or straw. Cattle and horses pull hay out of feed mangers, and it accumulates around the feeding area. This creates a fly breeding area. Other areas for the flies to breed are calving sheds, receiving areas, and hospital pens.

Stable flies used to be considered only a feedlot or farm problem, but now have spread to the pastures of Kansas and possible states to the east.

"A mixture of a little manure and urine along with hay on the ground is a perfect place for stable flies to breed," said Dr. Gerald Greene, an entomology consultant at Garden City, Kansas. Dr. Greene stresses clean-up of manure in the late winter and early spring before the flies hatch. This includes pastures where hay has been fed on the ground.

Stable Flies at the Feedlot
June and July are a bad time for stable flies at the feedlot. This appears to be a more serious problem for feedlots that feed high roughage grow rations. These high roughage rations have considerable undigested roughage particles from the hay and silage. This mixture with the manure is a good place for the stable flies to breed. Spilled high roughage feed that gets wet along a feed bunk can also be a breeding place.

Year to Year Variation
We have noticed some years are worse than others. Dr. Greene points out that after a wet winter and wet spring, which may cause a delay in cleaning of pens, the incidence of an outbreak of stable flies can be severe. Dr. Greene suggests piling wet manure is better than leaving it in the pens because the surface area for the breeding and hatching of stable flies is reduced. However, piling wet manure is more expensive to transport and spread due to the extra water it contains.

Dr. Greene and entomologists at Kansas State University have evidence that the flies in certain years are blown in on the jet stream wind from Texas, New Mexico, and Arizona.

Clean Pasture and Corrals in Early Spring
Either at the ranch or the feedlot, a good approach is to clean pens in early spring and prevent a buildup just before the hot spring weather sets in. Removing the manure from pens with no cattle is very important. Pens that have cattle activity are not suspected to be a breeding place for the flies. But care must be taken to clean up the areas of each pen where manure has accumulated and is not tromped down by cattle activity. Cleaning under the fences is also needed.

Horse Corrals
Stable flies are particularly bothersome for our ranch and feedlot horses. Cleaning the horse pens and corrals is also important to control stable flies.

Silage Around Bunker Silos
We have experienced an area of flies hatching around spilled, wet silage. Stable flies will also breed and hatch from piled grass clippings near homes. It is important to clean all these areas regularly, especially in early spring, to minimize the fly problem. ©

Questions or comments on this or any article by Dr. Jim Sprague can be directed to him at 625 Grandview, Newton, Kansas, 67114. Or call him at (316) 283-8692.