Measurement of and selection for insecticide resistance in various populations of beet armyworm Spodoptera Exigua (Hubner)

摘要

A comparative study was performed to investigate the tolerance levels of beet armyworm to three insecticides, cyfluthrin, profenofos, and methomyl. The field strains were collected from Yuma and Marana, AZ whereas the susceptible laboratory strain was obtained from California. Dosage-mortality data were obtained by topical application on third instar larvae. Compared to the susceptible strain, both Yuma and Marana strains exhibited an increase in the LD50 to cyfluthrin by 15.65 and 5.45-fold, respectively. Both strains also exhibited an increase in the LD50 to profenofos and methomyl by 14.10, 17.77 and 2.95, 8.07-fold, respectively. The cyfluthrin-selected strain (Marana strain) tested for cross resistance to profenofos and methomyl and exhibited an increase in LD50 by 24.68 and 3.32-fold,respectively.