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For:    Week of June 7, 2004

By:      John D. Atkins

Extension Agriculture/Livestock Agent

Santa Rosa County Extension Service

 

Protecting Florida Horses From Mosquitoes

 

Fly control for horses in Florida is crucial, both for the irritation they cause and as protection against disease. The most common equine mosquito-transmitted disease currently in Florida is Eastern Equine Encephalitis. The discovery of West Nile virus in north Florida in July 2001 increases concern about mosquito-transmitted equine disease and the need for mosquito control. The possibility of other exotic viruses entering Florida, such as Venezuelan Equine Encephalitis, is also of concern to horse owners. One method of disease prevention in horses is protection from mosquito bites.

 

There are many types of flies other than mosquitoes that affect horses. Most of the repellents and insecticides used against mosquitoes are also effective against other flies. However, other control methods are specific to groups of flies. Here, we will address only mosquitoes.

 

There are various methods which can be used to protect your horse from mosquitoes:

 

Population reduction           > Keep water-holding containers to a minimum.

> Dump out, put away or drill holes in anything that can hold water which isn’t needed for horse keeping.

> Water buckets and troughs should be dumped, cleaned and refilled regularly – at least every 3 days.

 

Stabling and Premise Sprays          > Stable horses during the dusk and dawn peak

   biting periods.

> Consider premise sprays and automatic spray

    systems.

 

Physical Barriers – Horse Clothing

                                                > Fly sheets

                                                > Face mask and ear nets

                                                > Leg wraps

 

Topical Insecticides and Repellents

 

• Pyrethrins, extracted from chrysanthemum plants. Very effective but often of short

  duration.

• Pyrethroids, synthetically developed compounds chemically very similar to pyrethrins.

  These are effective and have very low toxicity to mammals, and often longer-lasting

  than pyrethrins.

• Permethrin and cypermethrin, two of the more common pyrethroids.

• Piperonyl butoxide, a common synergist, to enhance effectiveness and persistence of

  the chemical.

• Other plant extracts used in fly sprays include citronella, eucalyptus, pennyroyal, cedar,

  and geraniol.

• DEET, the ingredient in many repellents for human use, has recently been approved

  for use on horses but is available only from licensed veterinarians. Because it is a

  repellent only, and has no insecticidal effect, it will have less impact on the overall

  mosquito population. This may be the best choice for a horse that is sensitive to

  pyrethroids.

• Sunscreens, primarily to protect the chemicals from degradation in the sun.

• Oil or water based carriers.

• Fragrances and coat enhancers.

 

Which combination will work the best? It depends on the horse and activity. A stabled show horse will require a different approach than a pastured trail horse. Frequently groomed horses may be best protected with a shorter-acting, frequently applied spray while pastured horses may need a longer-acting treatment resistant to rain. Read the labels and rely on trial and error observations! Test products on a small area first; some horses are sensitive to different chemicals (including those in plant extracts).

 

Some options include:

 

• Ready to use sprays - good for frequent use.

• Concentrates, diluted before use. Often convenient to modify the dilution according to

the current situation.

• Some sprays and concentrates can be used on premises as well as directly on horses.

• Lotions and gels - useful on legs and wounds.

• Spot on gels and lotions - longer acting, applied to specific sites on the horse and

  allowed to migrate through the hair coat. These may be effective and convenient for

  pastured horses.

 

For current information on West Nile virus and Eastern Equine Encephalitis virus activity in Florida, visit the Florida Medical Entomology Lab's Encephalitis Information System at

http://eis.ifas.ufl.edu.

 

John Atkins is Agriculture/Livestock Agent for Santa Rosa County.

 

Extension Service programs are open to all people without regard to race, color, sex, age, handicap or national origin.