Prevention of screwworm infestation in cattle by controlling Gulf Coast ticks with slow release insecticide devices.

Field trials were conducted on 8 southern Texas ranches from July through Oct., 1976, to evaluate the effectiveness of insecticide-impregnated ear tags, ear bands, neck bands, and asphalt base aerosols for the control of the Gulf Coast tick, Amblyomma maculatum Koch, on cattle. A 15% stirofos ear tag was the most effective device tested; however, the 10 and 20% chlorpyrifos ear tags, and 10% propoxur neck band provided generally satisfactory control of the Gulf Coast tick and protected test animal’s ears from infestations by the screwworm, Cochliomyia hominivorax (Coquerel). All 3 kinds of ear tags so reduced tick attachments during 10–14 weeks of testing that none of the tag-treated ears attracted ovipositing flies, whereas half of the control animals became infested with screwworms. Numerous physical problems were encountered with the ear band treatments which made them impractical for use on cattle. Neck bands were less effective than ear tags. The asphalt base aerosols were effective for only 4 weeks.