Parasiticide resistance in flies, lice and ticks in New Zealand and Australia: mechanisms, prevalence and prevention

AbstractThis review outlines the history of parasiticide resistance in the principal ectoparasites of sheep and cattle in New Zealand and Australia, blowflies, buffalo fly (Haematobia irritans exigua), sheep biting louse (Bovicola ovis) and cattle ticks, and discusses recent changes in their response to insecticides and acaricides. Mechanisms of resistance and evaluation methods are described, with ways in which insecticide resistance can be avoided or ameliorated also discussed.Resistance in sheep blowflies (Lucilia cuprina; L. sericata) to organophosphates and benzoylphenyl urea compounds is widespread in Australia and New Zealand, but there are lesser concerns about a pyrimidine carbonitrile product as well as cyromazine and macrocyclic lactone actives which still offer the promise of long-term protection. In Australia the effectiveness of synthetic pyrethroid and benzoylphenyl urea products against the biting louse of sheep have been reduced by widespread resistance but effective temephos, macrocyclic...