Efficacy of Crotoxyphos Sprays for the Control of the Southern Cattle Tick in Puerto Rico

Abstract

Field trials were conducted near Cabo Rojo and Mayagüez, Puerto Rico, to evaluate the efficacy of crotoxyphos (afpha-methylbenzyl 3-hydroxycrotonate dimethyl phosphate) applied as a whole-body spray to cattle for control of the southern cattle tick, Boophilus microplus (Canestrini). Percent control was determined by comparing numbers of 4.5- to 8.0-mm-sized engorged females present on control and treated animals on days 0, 1, 7, 14, and 21 posttreatment. Crotoxyphos at concentrations of 0.49 to 0.015% a.i. afforded an average control in excess of 92% (92.9 to 99.8%) for all concentrations. Differences in percent control of ticks between concentrations and also between days on which counts were made were determined by analysis of variance to be statistically nonsignificant.