Acaricide resistance--back to basics.

Resistance like life is poorly understood and like death is inevitable (but will take varying times to develop). Resistance develops rapidly where the gene frequency for resistance is high and there is increased selection pressure. Resistance should be seen in perspective and can be managed. For example resistance is most frequent in single-host ticks which transmit less serious diseases. Indeed where products are also used to control tsetse, it may be more important to have live cattle with the risk of tick resistance, (which may in any case take years to develop) than severe losses through trypanosomiasis. Good management can prolong the active life of compounds and the following practical considerations should be adopted:- Field training to ensure the correct usage of products. Ensure ticks are not transported with animals. Establish tick resistance testing centres.