Comparative Toxicity of Some Conventional Insecticides Against Culex Pipiens L. Mosquito Larvae from Different Districts in Egypt

Abstract

The susceptibility of Culex pipiens larvae to some insecticides commonly used in mosquito control programs ]cypermethrin (Sparkill ® ), deltamethrin (Embrator ® ), temephos (Temepest ® ) and spinosad (Tracer ® )[ was investigated, also variations in esterases and glutathione S-transferases (GST) activities among three field populations (Abou homoss, Nadi El Said, Montaza) were measured and compared with a laboratory susceptible strain (S). The highest level of resistance against the tested insecticides was found in Abouhomoss strain (27.3, 22.2 and 24.8-fold) and the lowest level of resistance was recorded in Montaza strain (12.75, 15.17 and 8.17-fold) towards cypermethrin, deltamethrin and temephos, respectively. On the other hand, all strains recorded no resistance against spinosad (Tracer®). All field strains revealed significantly higher levels of GST and esterases activities compared with the laboratory susceptible strain. The results of the present study suggest that esterases and glutathione S-transferases enzymes have major role in Culex pipiens resistance to the evaluated insecticides.

Larvicidal evaluation of two novel cationic gemini surfactants against the potential vector of West Nile virusCulex pipiensLinnaeus (Diptera: Culicidae)

“…pipiens larvae, collected from an agricultural area (Kerdasa, Giza), showed a high level of resistance, although spinosad was very effective against lab strain larvae. These observations agree with those of Moselhy et al (2015), who revealed that the Giza field strain exhibited high RR (11.231 folds) against spinosad at 48 h. This might be due to the intensive application of insecticides in this area, which leads to the development of resistance (Zahran, 2014). Therefore, gemini surfactants may offer feasible alternatives to both plant products and traditional synthetic insecticides.…”