Glass-vial bioassay to estimate insecticide resistance in adult tarnished plant bugs (Heteroptera: Miridae)

A glass-vial bioassay was developed for use in estimating resistance to insecticides in adult tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois). When laboratory-reared insects of known age are used, the bioassay procedure requires that adults are not older than 10 d Testing each sex separately was not required, and each glass-vial (treated on its inside with an insecticide) received a piece of green bean, Phaseolus vulgaris L., as food for the adults tested. Two or 3 adults were placed in each vial; mortality was determined after 24 h of exposure in the vial. The bioassay was used to determine insecticide resistance in 3 groups of tarnished plant bugs to 10 different insecticides. Significant differences in resistance among adults were found from the 3 groups with most of the insecticides. Data obtained with this glass-vial bioassay can be compared with data obtained from bioassays that use plant bugs collected from cotton, Gossypium hirsutum. L., fields in which control with insecticides has been inadequate.