RESUMO
OBJECTIVE: To understand the cross-resistance of Culex pipiens pallens to common pesticides, so as to provide the evidence for improving the application of chemical pesticides. METHODS: The IV instar larvae of DDVP-resistant, propoxur-resistant and cypermethrin-resistant strains as well as the sensitive strain of Culex pipiens pallens were collected to detect the resistance to DDVP, propoxur and cypermethrin based on the WHO bioassay method. RESULTS: The resistance coefficients of DDVP-resistant strain to DDVP, propoxur and cypermethrin were 14.47, 8.96 and 207.27 respectively. The resistance coefficients of propoxur-resistant strain to DDVP, propoxur and cypermethrin were 3.27, 6.93 and 8.65 respectively. The resistance coefficients of cypermethrin-resistant strain to DDVP, propoxur and cypermethrin were 2.93, 1.61 and 501.11 respectively. CONCLUSION: The resistance and cross-resistance could be generated during the long-term application of a single kind of chemical pesticide, and we should pay more attention to the varieties and dosages of them.