Biological and Chemical Fly Control
Maxine Kinne

Nothing is quite so aggravating as having pesky flies treat your bare skin like a landing strip in the hot summer months. The few that get into the house can easily be dispatched with a handy swatter, but the majority live in the barn where they breed like... well... flies. Besides being annoying, flies can spread disease, contaminate milk and meat, and lay eggs in wounds. If you have a fly problem, it's a good idea to implement a good control program before they get entrenched in the spring.

Manure management and sanitation are the first line of defense against a fly population run amok. Flies breed in manure, especially in bedding material over 30% moisture, so good drainage and weekly bedding changes interrupt their life cycle and eliminate their breeding environment. Paranoid cleanliness now will reduce the number of flies you will have around to curse later.

Ideally, your neighbors would share your habits of hygiene. Unfortunately some folks are sanitarily challenged, and you'll have to deal with their flies who have no respect for property lines.

Biological Control

Chickens and ducks, particularly Muscovies, eat flies and fly larvae. They also clean up grain spills and lay eggs. Chicken and duck poop is one of the biggest complaints about poultry, so if you choose this route, limit their numbers to what you want to handle. Make sure the chickens don't nest in your hay feeders as they carry goat parasites in on their feet leading to heavier internal parasite loads in your goats. You'll have to change water frequently if you keep ducks because they like to take frequent dips. Like half a dozen times a day. In the goats' watering trough! A creative watering system will get around this problem.

A friend in muggy Florida swears that using diatomaceous earth (DE) works to keep flies under control. DE is finely powdered diatoms, the skeletal remians of one-celled algae found in geological deposits, which is mined for several purposes. Use only food grade DE around animals because the kind available at your swimming pool supply contains a high level of lead. Two mail-order suppliers are: Necessary Trading Company (800-447-5354), and Integrated Fertility Management (800-332-3179). DE is sprinkled on bare ground before bedding is put down, then it is applied weekly. Keep your animals away from the treatment area, and do not to breathe this product. It is very abrasive to the lungs and can cause a lot of damage. To avoid the dust, you can make a watery slush of it and spray with a hand-held or back-pack sprayer.

Parasitic wasps (hymenoptera) are a commerically-produced, host-specific natural enemy of the fly. These predators feed on fly larvae to interrupt the fly's life cycle and are not harmful to livestock or people. Since these insects reproduce much slower than flies, you need to order and "seed" them into your environment periodially. Some catalog companies offer this resource. Spalding Laboratories and other suppliers offer a variety of automatic shipment programs that can easily be tailored to your needs so that batches of fly parasites arrive at periodic intervals. There are probably many outlets on the Internet for this wasp, so look for a source close to you to save on shipping.

There are numerous sticky strips and trapping containers available. Hang the sticky strips high enough to avoid walking into them - they're murder on a good hair-do. Husbands do not like to be caught in this manner and will complain louder than a goat having its annual boosters.

Several kinds of jar or bag traps come with fly attractant designed to lure the irksome insects to their deaths. Traps develop a foul odor, but I like to think of it as the odor of success. I like the plastic-domed Trap "N Toss. It is disposable, but I cut a hole in the top to periodically flush the contents out with a hose so it is reusable. I put a piece of masking tape over the hole after flushing. For bait I use pieces of placenta which are cut into usable sizes and stored in ziploc bags in the freezer until needed. (Oh, all right, so I've lost my delicate sensibilities...)

A pheromone fly attractant strip placed inside or very close to a bug zapper is said to work great. Bug zappers have the added benefit of attracting and incincerating mosquitoes and other bothersome flying insects.

Chemical Control

Pyrethrin sprays are safe to use on and around livestock. If the label says it is safe to use on or around lactating dairy cattle, it will be safe to use around the goats. It has a residual effect but should be used periodically - you'll know when. Such products can be sprayed using hand-held equipment, or you can buy automatic foggers or misters for continuous dispensing. (I wrote this before moving to hot, humid Texas where flies don't seem to die. At some times of the year it was necessary to spray the entire barn with Permectrin II before I could stand to do the daily chores. Then I sprayed again afterward. The goats had no bad reaction to the large amounts I used.)

A number of bait products can be used. Baits usually contain sugar or can be mixed with it and set in appropriate locations. Golden Malrin, Apache, Dibrom Fly Killer D are a few brand names. Some of these can be put in used plastic containers with water added in appropriate amounts and hung in the barn. When these poison products are used dry, they need to be sprinkled in areas where goats, pets and children cannot get at them. Read the labels for suitability in dairy situations.

The relatively new pour-on insecticide, Cylence, takes care of both biting and sucking lice, and it is marketed as a fly control product. I used it briefly in Texas but not for long enough to see that it works as well as other producers have told me about. It's supposed to be Very Good, and I would use it if I still had critters.

As you can see, there are lots of ways to commit fly-icide. Take your pick and get a jump on the fly season.


Related Reading

Tips on Fly Control from Dairy Biz
Fly Control on Animals


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