Inheritance of diazionon resistance in the Biarra strain of the cattle tick (Boophilus microplus) in Australia

Abstract

The organophosphorus-resistant Biarra strain of the cattle tick, B. microplus, from southern Queensland was crossed reciprocally with a susceptible reference strain and the resistances of these parental strains to diazinon were compared with those of F1, test cross, and F2 larvae. The data obtained were in agreement with expectations for one inconlpletely dominant autosomal gene or several closely linked genes controlling resistance. The degree of dominance at LD50s ranged from +0.488 to . + 0.622. Homozygotes and heterozygotes were respectively 20-36 and 9.5-18 times as resistant to diazinon.