EFFICACY OF A COMBINATION NECKBAND AND TAILTAG CONTAINING AMITRAZ OR CYHALOTHRIN-K AGAINST LONE-STAR TICKS ON PASTURED CATTLE

A neckband and tailtag containing either amitraz or cyhalothrin K were placed on individual cattle to test the effectiveness of the devices for the control of adult Amblyomma americanum (L.). The neckbands and tailtags were fabricated from either strips of ethylvinyl acetate cont aining 10% amitraz or from eartags containing 10% cyhalothrin K. Both types of neckbands contained 6 g of acaricide, and 1 g of active ingre dient was in each tailtag. Because it was not possible to implement an experimental design that kept treated and untreated animals in separa te pastures, in the first of three tests of the amitraz neckband and t ailtag, close contact among the treated and untreated heifers resulted in parallel decreases in the numbers of ticks on animals in both grou ps. Mature cows were used in all subsequent trials to minimize contact between animals. The results of the second test with amitraz and the single test of neckbands and tailtags containing cyhalothrin K were si milar with a mean control of 87.3% for 90 d with amitraz and 89.4% for 94 d with the devices containing cyhalothrin. The final trial with am itraz was begun too late in the spring to completely test the persiste nce of the effect from the neckband and tailtag, but a mean percent co ntrol of 93.3% was maintained for 59 d before the seasonal decline in adult tick activity occurred.