Susceptibility status of field populations of Rhipicephalus bursa (Acari: Ixodidae) to pyrethroid insecticides

Rhipicephalus bursa is a two-host ixodid tick with wide distribution in north of Iran especially in Mazandaran province. Acaricide treatment is the main tick control measure; however, acaricide resistance occurs in hard ticks in many areas of the world including Iran. Comprehensive information on susceptibility status of Rhipicephalus bursa is lacking, therefore, this study is undertaken to determine the susceptibility status of the species to pyrethroid acaricides and probable biochemical underlying mechanisms of resistance. From May 2013 to March 2014, engorged females Rhipicephalus bursa were collected using standard entomological procedures from body surface of sheep, goat and cattle in different areas of Mazandaran province, northern Iran. Eleven and ten pooled tick populations were tested against cypermethrin and lambda-cyhalothrin, respectively using larval packet test. Population SC-16 showed a maximum resistance ratio of 5.79 against cypermethrin in Sari County when compared to the most susceptible population NH-16 and 63.64% of tick populations were resistant at LC₉₉ level. With lambda-cyhalothrin, 30% of the tick populations were resistant with low level and NK-2 was the most resistant population with resistance ratio of 4.32 in Nowshahr County. The results of biochemical assays demonstrated elevated levels of monooxygenases, glutathione S-transferases and esterases in pyrethroid resistant populations tested.