Study on the sensitivity of Aedes albopictus to common insecticides in Wuhan.

Objective To investigate the sensitivity of A. albopictus to commonly used insecticides in Wuhan, providing the guidance in the control of mosquitoes. Methods A total of 1 847 larvae and 302 pupae were collected from the field population of Ae. albopictus in Wuhan. The larvae were reared to F1 generation in the laboratory, and the larvae were the third instar larvae of F1 generation. The sensitivity of larvae to different insecticides (96.85% deltamethrin, 99.00% permethrin, 87.40% disphos, 95.56% propoxur, 97.00% pyripropyl ether, 95.00% S-enyl ester, 98.70% difenuron) and 7 000 ITU / mg Bti were determined by immersion method. After the second instar larvae of Aedes albopictus were parasitized by Nematode Wuchang, the death rate of larvae was calculated and the survival curve was drawn. Results The median lethal concentration (LC₅₀) of the larvae against temephos, deltamethrin, permethrin and propoxur were 0.023 40, 0.036 37, 0.200 0 and 1.562 9 mg/L respectively, relative sensitive to temephos and deltamethrin. The inhibition emergence concentration (IE₅₀) of the larvae against S-methoprene, pyriproxyfen and diflubenzuron were 0.000 310, 0.000 412, and 0.009 594 mg/L, respectively, relative sensitive to S-methoprene and pyriproxyfen. The LC₅₀ of the larvae against Bti was 0.002 697 mg/L, and the mortality rates of mosquito larvae were 77.42% and 95.04% at the infection ratio of mosquito larvae to nematodes=1:5 and 1:10, respectively, which were highly significantly different from the control group (P<0.000 1). Conclusions Temephos and deltamethrin can be used as a quick method to control A. albopictus larvae in Wuhan city, and the insect growth regulators such as S-methoprene and pyriproxyfen also can be used as an environmentally friendly insecticides. R. wuchangensis is also highly efficient for mosquito larvae control. [ABSTRACT FROM AUTHOR]