Economics of Controlling Horn Flies (Diptera: Muscidae) in Range Cattle Management1

Abstract

Yearling stocker calves and mother cows were treated with either stirofos (Rabon®) or fenvalerate (Ectrin®) ear tags to control Haematobia irritans (L.) at Woodward and EI Reno, Okla., in 1979, 1980, and 1982. Stirofos tags in 1979 failed to provide acceptable control and resulted in only a 2.8% gain in weight. Fenvalerate tags (two tags per head) used in 1980 and 1982 at Woodward, Okla., resulted in excellent horn fly control and gain in weight from 11 to 14.3%. In 1981, at El Reno, Okla., calves from fenvalerate-treated cows outweighed calves from untreated cows by 7.4 kg per head at weaning. These increases in weight resulted in returns ranging from $2.16 to $8.38 per $1.00 spent on insecticides for fly control. These differences were obtained when treated animals were essentially free of H. irritans and untreated animals had as many as 700 flies each.