摘要：Rhipicephalus microplus, the cattle tick, is widely distributed across many tropical and subtropical regions of the world and has been identified as the most economically important species of tick across a number of countries. Quarantine boundaries currently limit the spread of the cattle tick into northern New South Wales, parts of South East Queensland, the central parts of the Northern Territory and northern parts of Western Australia. The Queensland tick line (or quarantine boundary) largely follows the 500mm rainfall isohyet until it reaches southern Queensland. As the cattle tick is unlikely to become endemic to regions receiving median rainfall less than 500mm per annum, the region most likely to be effected by a deregulation of the tick line is located in the south east corner of the State “inside” the 500mm isohyet but “outside” of the tick line. There are a number of strategies available to beef producers running susceptible cattle within the region impacted by a deregulation of the tick line. For example, they could: o choose to apply acaricides into the foreseeable future, o choose to breed tick resistance into their livestock and apply acaricides during the conversion period, o replace their susceptible breeding herds with tick resistant stock from within the tick endemic region, or o continue with susceptible livestock and implement sufficient quarantine and pest management strategies to reduce the risk of tick infestation to a negligible level The economic evaluation of these strategies indicates that the total costs of deregulation depend upon the type of response made by industry and the level of that response.
