Comparative toxicity of chlorphenapyr to Musca domestica adults of different lines

The aim of the study is to compare the toxicity of chlorfenapyr for M. domestica of different lines, includ-ing the natural population living in the Tyumen Region. Objectives: to establish the sensitivity of these lines to chlorfenapyr by calculating lethal concentrations and the resistance index. The objects of the study are individuals of two laboratory lines (Lab TY and Lab UF), previously not exposed to insecticides, and the natural population Nik. The Lab TY line was obtained from the Novosibirsk Agrarian University in 2009, the Lab UF line – from the Institute of Biochemistry and Genetics of the Ufa Federal Research Center of the Russian Academy of Sciences in 2023. Individuals of the natural population Nik were caught in May – September 2023 in livestock buildings in the Sladkovsky District of the Tyumen Region. The contact-intestinal action of the insecticide (Pirafen, EC, active ingredient chlorfenapyr, 360 g/l) on M. domestica was assessed using the group feeding method. The experiment was conducted in laboratory conditions, where the insects were exposed to chlorfenapyr in various concentrations. The mortality of insects was recorded 24, 48, and 72 hours after exposure to the insecticide. Insects unable to move and fly were con-sidered dead. The results of toxicological tests were analyzed by probit analysis to calculate lethal concen-trations (LC5, LC50, LC95 – concentrations at which 5; 50; 95 % of the experimental insects die, respec-tively) using the free version of the program. Differences in two LC values were considered statistically significant if the corresponding 95 % confidence intervals did not overlap. Imagoes of both laboratory lines were similar in sensitivity to the insecticide chlorfenapyr. Individuals of the natural population were highly sensitive to chlorfenapyr, which indicates the prospects for using preparations based on it in the field of veterinary disinsection.