Livestock Insects–Horses

Black Flies

John B. Campbell 

Mosquitoes are a serious problem for horses because they transmit encephalitis (primarily eastern and western strains) and most recently, West Nile virus. Vaccinations are available for these diseases and should be given in the spring prior to the advent of mosquitoes. West Nile virus requires two shots about 14 days apart. Black flies attack horses in the ears and insecticides or salves can be used to treat in the ears. Horse and deer flies (Tabanids) would require the same treatments as do cattle but use only insecticides labeled for horses. Insecticides approved for use on horses are listed at the end of this chapter.

Insecticides Suggested for Treatment of Flies on Horses:
Insecticide	Application Method	Application Rate	Restrictions and comments
Coumaphos (Co-Ral) (Co-Ral Fly and Tick Spray) (Co-Ral)	Spray or Sponge Spray Spray	11.6 % ELI 1 pt/25 gal water 6.5 % EC 2 qt/50 gal water or 10 oz/4 gal water 25 % WP 4 oz/12.5 gal water	Restricted-use Pesticide For horses not intended for slaughter. No more than 6 treatments per year, no less than 10 days apart.
Fenvalerate (Ectrin)	Spray	10 % WDL 2 oz/12 gal water	Apply 8 oz of diluted spray per horse. Do not apply to horses intended for slaughter.
Methoxychlor	Spray or wipe-on	0.05 % Ready to use	Follow label instructions.
Permethrin (Atroban) (Buss Off) (Ectiban) (Gardstar) (Permectrin II)	Spray Wipe-on, Spray or Pour-on Spray Spray Spray	11 % EC 1 pt/25 gal water or 3 tbsp/2.5 gal water 7.4 % Permethrin + 7.4 % PBO 5.7 % EC 1 qt/25 gal water or 22 tbsp/1 gal water 40 % EC 5-12.5 ml/2 gal water 10 % EC 2 oz/3 gal water	Spray to thoroughly wet animal. Repeat every 10-14 days. Repeat application every 14 days. Apply 30-60 ml per horse. Spray thoroughly to wet horse. Repeat in 14-21 days.
Pyrethrins	Mist, spray or wipe-on	0.05-1.0 % Pyrethrins + Piperonyl Butoxide Many formulations of ready to use.	Follow label instructions.
Stirofos (Rabon)	Feed Additive	7.76 % ROL	Follow label directions. Horn and face fly control only.
The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.

Categories: Livestock insects, Horses, Black flies

Date: 03/28/2003