Comparative in vitro evluation of deltamethrin and dichlorvos against chicken lice and mites

In vitro bioassay was carried out to determine the efficacy of deltamethrin (DMT) and dichlorvas (DCVP) against lice and mites through filter paper method. The lice and mite samples collected from the infested flocks were used for the in vitro bioassays. The different concentrations of DMT and DCVP with and without surfactant (soap oil) were applied against feather mites, shaft louse and wing louse. Mortality of ectoparasites was observed in time interval of 2, 5 and 30 minutes. The concentrations at the rate of 1000 ppm (0.1%), 400 (0.04%) ppm and 200 ppm (0.02%) of DMT and DCVP with surfactant for feather mites, shaft and wing louse treated groups caused 100% of mortality in 30 minutes post treatment respectively. The lethal concentrations LC₅₀ values for DMT with surfactant were 250.03, 40.98 and 20.64 ppm and LC₉₉ values were 5605.96, 1036.90 and 238.07 ppm, while for DCVP with surfactant LC₅₀ values were 473.90, 100.00 and 134.79 ppm and LC₉₉ values were 1413.51, 679.34 and 2089.65 ppm for feather mites, shaft louse and wing louse respectively in 30 minutes of lethal time interval. The study emphasized the role of surfactant in potentiating the efficacy of both deltamethrin and dichlorvos on account of lesser LC₅₀ and LC₉₉ values with surfactant against Megninia ginglymura, Menopon gallinae and Lipeurus tropicalis than without surfactant.