Pyrethroid tolerance in the chewing louse Bovicola (Werneckiella) ocellatus

In vitro effect of seven essential oils on the reproduction of the cattle tick Rhipicephalus microplus

“…The economic impact caused by cattle ticks in Brazil is of approximately $3.24 billion dollars a year [1] since climatic conditions are favorable to their survival and development [3], increasing control costs with synthetic acaricides [4]. Moreover, restrictions on the use of insecticides and acaricides, such as organophosphates due to their effects on human and animal health [5], and the environment [6] have enhanced the development of effective alternatives for control, including essential oils.…”

First report of deltamethrin tolerance in the cattle chewing louse Bovicola bovis in the UK

“…Treatment is usually by the use of topical insecticides such as synthetic pyrethroid and macrocyclic lactone formulations. Recently, there have been concerns over the development of pyrethroid resistance in chewing lice (Ellse and others 2012, Levot 2012). Inadequate coverage of the body resulting from pour-on and spot-on formulations exposes lice distal to the zones of drug penetration to sublethal doses of insecticide, which potentially exacerbates selection for resistance (Johnson and others 1995, Ellse and others 2012).…”

“…Recently, there have been concerns over the development of pyrethroid resistance in chewing lice (Ellse and others 2012, Levot 2012). Inadequate coverage of the body resulting from pour-on and spot-on formulations exposes lice distal to the zones of drug penetration to sublethal doses of insecticide, which potentially exacerbates selection for resistance (Johnson and others 1995, Ellse and others 2012). Facultative parthenogenesis may also allow populations of lice with alleles conferring resistance to increase rapidly in size and predominate within the overall louse population (Ellse and others 2012).…”

“…Inadequate coverage of the body resulting from pour-on and spot-on formulations exposes lice distal to the zones of drug penetration to sublethal doses of insecticide, which potentially exacerbates selection for resistance (Johnson and others 1995, Ellse and others 2012). Facultative parthenogenesis may also allow populations of lice with alleles conferring resistance to increase rapidly in size and predominate within the overall louse population (Ellse and others 2012). To date, there has been no clear evidence of insecticide tolerance or resistance in the UK B. bovis populations.…”

“…Immersion in such oils has been shown to result in high mortality in Bovicola (Talbert and Wall 2012) probably as a result of blockage of the spiracles causing suffocation. It is likely that the high toxicity of the undiluted deltamethrin product may, at least in part, be attributed to the mechanical effects of the oily caprylic triglyceride excipient (Ellse and others 2012). …”