There are over one million known species of insects in the world. Thankfully only a tiny percentage of insects are an issue for people and livestock. But those few insects can cause a major nuisance and seriously affect your profits whether you run a dairy, feedlot or are a grazier. This guide focuses exclusively on flies as they are the worst problem insects for most livestock owners.The good news is that flies can be managed just like you manage every other element of your operation. Our belief is that effective fly control can make you money, not cost you money. You can not only gain a much more pleasant environment for your family, but by reducing fly stress the typical summertime fall off in milk production will be lower and often more than pay for the cost of good fly control. The same can be true for beef cattle as fewer flies usually mean greater weight gain.
By gaining some basic understanding of fly biology, particularly what encourages and discourages their reproduction, you can reduce their numbers to tolerable levels, with no or only a minimal use of insecticides. Often the simple release of Fly Predators, plus modest improvements in manure management, is all that is needed. More comprehensive approaches, including initial careful and selective use of insecticides, may be necessary for the fastest control if the pest fly problem has been allowed to become severe. This is because most of the “natural” controls prevent future flies, but do not affect existing adults. Since adult flies live approximately 21 days, you will either need to put up with them for that long or use traps and baits or careful pesticide application to reduce their population rapidly.
The first step is to identify the insect(s) that are plaguing you and your animals. This is important as the variety of flies that bother you can come from dramatically different sources. For example, House Flies primarily reproduce in moist (not too wet and not too dry) manure, but Biting Stable Flies prefer rotting vegetation (spoiled feed and silage) over cow manure. Horn Flies reproduce only in pastured cattle manure that is undisturbed. Knowing where to attack the problem is essential.
Most of the common pest flies are easy to identify by comparing one with the following illustrations. You can also tell by simply looking at your animals. If the flies are primarily on the legs or flanks, causing the cows to bunch and stomp, those are Stable Flies. If they are small and primarily on the back, those are Horn Flies. House Flies can be anywhere but they will be the only large flies on the face going to the eyes with confined animals. If you are grazing those may be Face Flies or House Flies. When identified then focus on the prevention and control of that species.
Every summer we visit customers all across the country during the peak of fly season. The photos on this page are un-retouched close ups from the farms of the folks you see on this site.
Dr. Bill ClymerFort Dodge Animal Health, Dr. Roy EllisPrairie Pest Management, Dr. Kevin FloateAgriculture and Agri-Food Canada, Dr. Robert M. Miller, DVM, Dr. William QuarlesBio-Integral Resource Center. All illustrations 2006 Dr. Roy Ellis.
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