By DONNA JAHNKE
Indiana Correspondent

DANVILLE, Ind. — There is such a wide variety of fly sprays on the market that choosing the right one can be confusing.

Most include an insecticide with a repellent, either in a water or oil base. The prices and effectiveness can vary depending on the quantity and quality of the ingredients.

The most common ingredient is pyrethrin. According to the EPA’s website, more than 3,500 products have pyrethrin as its primary ingredient. It is derived from chrysanthemum cineraiaefolium. It acts as a neurotoxin working on the nervous system of the insect. Many fly sprays use this chemical but in varying amounts.
Often, it is paired with permithrin, which is a synthetic version of pyrethrin. According to the University of Kentucky, “pyrethrins are effective but do not last as long as permithrins.”

The ingredient seen most with both pyrithrin and permithrin is Piperonyl Butoxide. This chemical isn’t an insecticide. However, when added to insecticides, it greatly increases their efficacy.
It works on the insect to allow the insecticide to become more effective, by allowing it to remain in the insect for longer periods.
Dr. Terry Brandenburg, DVM, has used both pyrethrin sprays and natural sprays. Both have worked well, he said. Brandenburg said he uses the natural spray usually on a daily basis. He uses pyrithrin sprays, as needed. He suggests using the spray a little heavier on the legs, where animals are prone to rubbing it off.

One of the more common repellants is citronella. While it has no ability to kill insects, it has been used for more than 50 years as a repellent. According to the EPA, “it works by having a distinct odor which may make it difficult for some pests to locate the host.”
There are many herbal fly sprays on the market. While they do not carry an insecticide, they use citronella and other oils - such as eucalyptus - to repel insects. For those troubled by inhaling insecticides, this may be a good fit.

The base for fly sprays is usually water or oil. Water-based sprays are good for show animals, as it doesn’t attract dust. Oil-based sprays, though, may last longer.

Brandenburg cautions against using oil-based general livestock sprays on horses.

“Some horses have had a chemical reaction causing a mild burn and occasionally hair loss,” he explained.

Many homemade fly spray recipes recommend using a diluted mix of apple cider vinegar. Some mix it with citronella oil. Others mix it with liquid dishwashing soap. Though many people believe in its effectiveness, it has not been tested.

Keeping the barn as clean as possible will also help to control flies. Brandenburg said he rarely uses a premise spray, but instead makes sure that all manure is removed on a daily basis.

There are many fly sprays that are in a concentrated form.
This is an economical way of using fly spray. Another benefit is that most give two different ratios to use. A regular dilute and another, higher concentration for heavily infested areas.

Fly sprays also come in different dispensers. Roll-ons are available to use on faces or around wounds. Aerosols work well as premise spray. Wipe-on is another option.

Obviously, the higher the concentrate of insecticide is not the only thing to consider when purchasing. Many sprays work well on their repellent qualities. The optimum spray will depend upon the users needs.