LABORATORY SELECTION OF MUSCA DOMESTICA WITH DICHLORVOS AND LINKAGE TO ACTIVITY OF ACETYLCHOLINESTERASE AND CRBOXYLESTERASE IN MUSCA DOMESTICA IN BEIJING

Laboratory selection for resistance strain with Dichlorvos (DDVP) was carried out in strains of houseflies Musca domestica collected from Haidian district, Beijing, China. Resistance increased gradually from F_0 to F_5, and appeared a platform between F_6 to F_14 and increased significantly from F_14. The resistance of the F_20 generation, selected by DDVP, was 35 folds in comparison with the susceptible strain. Resistance selection to DDVP has no effect on AChE activity, but Carboxylesterase(Est) activity of DDVP-resistant housefly was higher than the susceptible strain. Reduced sensitivities of AChE and Est to DDVP were associated with resistant level. The study suggested that both increased activity of Est and reduced sensitivities of AChE and Est to inhibitors may be the main resistance mechanisms of houseflies to DDVP.