Effect the selective pressure on the resistance development in culex molestus mosquitoes as a result of using the extracts of Myrtus communis and the larvicide Mozkill

The present study was conducted with the aim of evaluating the sensitivity of the domestic mosquito Culex molestus Forskal in the Holy City of Kerbala and the effect of selective pressure for extracts of Myrtus communis and Mozkill in fourth-instar larvae of mosquitoes on the appearance of resistance The results of the study showed the presence of susceptibility in the Cx. molestus mosquito strain for plant extracts and Mozkill after three generations, where the LC50 values were (0.72, 0.77, 0.2) mg/ml, respectively, for cold and boiled Myrtus extract and hexane, And for Mozkill, the LC50 value was (1.01) mg/ml, and the strains were more sensitive to Myrtus extracts compared to larvicide Mozkill. The results of the selective pressure with plant extracts and larvicide Mozkill showed the appearance of resistance when the insect was exposed to these substances for six generations, where the LC50 values increased to (5.19, 4.29, 2.8) mg / ml, respectively for cold and boiled water extract and hexane of Myrtus and the LC50 value of Mozkill was (5.67) mg/ml in the sixth generation, compared with (1.21,1.26, 0.69) mg/ml in the generation of parents, and it was clear that there was an increase in the resistance ratios of the mosquito strain with the progression of generations, and it was In the generation of parents (1.68, 1.63, 3.45) times, it rose to (5.60, 4.86, 8.72) times in the third generation and (7.20, 5.57, 14.0) times in the sixth generation for cold and boiled ace extract and hexane, and for the resistance ratio in larvicide Mozkill it was (3.77) times and in the sixth generation it reached (5.61) times, and the development of resistance is evident in Mosquito strains treated with plant extracts and larvicide Mozkill.