In some areas, this may only be in certain years, when weather conditions are especially favourable for tick survival. The Walpole situation Following the discovery of the bush tick at Walpole in 1983, farms in the district were inspected annually for several years to determine the extent of establishment. The tick is now established on farms in the Walpole and Hazelvale districts, but usually in such low numbers that it is not noticed. On only two farms have populations approaching a significant level been seen, and these involved only a small number of stock. In this area, adult ticks are usually first seen in November, reach peak numbers in December, and decline during January.
Cattle are the chief hosts, but minor burdens have been found on sheep and dogs.
The source of introduction to Western Australia has never been traced, and it is possible that the tick had been present for some years before a favourable year allowed the population to increase to a noticeable level. It now appears that the Walpole environment is poorly suited to the bush tick. Because the climate is drier and hotter in summer than are areas where the bush tick thrives, it is probable that it has established only in preferred locations. On most properties, the pasture is relatively short and dry in the period when tick eggs are deposited and very few develop in this situation. Areas which could harbour ticks should be readily identified and would usually occupy only a small part of a farm.