Monitoring Insecticide Resistance in Greenhouse Whitefly (Homoptera: Aleyrodidae) with Yellow Sticky Cards

Abstract

The use of a yellow sticky card coated with one of three insecticides mixed with a polybutene insect trap adhesive was investigated as a resistance monitoring technique for greenhouse whitefly, Trialeurodes vaporariorum (Westwood). The technique provided accurate estimates of the mortality response of whiteflies after 24 h, with minimal control mortality (usually < 5%). The technique was used to estimate diagnostic concentrations (LC99 of a susceptible strain) for dichlorvos, resmethrin, and bifenthrin. The diagnostic concentrations were then tested against the susceptible strain and a resistant strain. These concentrations consistently killed approximately 99% of susceptible whiteflies in contrast with the resistant strain. Although the differences were not significant, adult males tended to be about twice as susceptible as females to all three insecticides. Mortality at the diagnostic concentrations was significantly and linearly correlated with mortality of both larvae and adults for resmethrin and bifenthrin in greenhouse applications, but only for adult mortality after treatment with dichlorvos. The technique provides a simple, rapid way to monitor insecticide resistance in greenhouse whitefly in the greenhouse or field. The degree of resistance to bifenthrin did not change substantially after 15-18 mo without insecticide exposure.