Response of Larval and Adult Obliquebanded Leafroller (Lepidoptera: Tortricidae) to Selected Insecticides

Abstract

Obliquebanded leafroller, Choristoneura rosaceana(Harris), larvae from a commercial apple orchard in western New York State were 36.8-fold, 2.5-fold, and 5.2-fold more tolerant to azinphosmethyl, chlorpyrifos, and esfenvalerate, respectively, when compared with larvae collected from untreated habitats. However, this relationship was not the same for male and female moths from the same locations treated with the same insecticides. Female moths were more tolerant to all insecticides than were males. Field applications of azinphosmethyl and chlorpyrifos did not reduce fruit damage at harvest compared with the untreated control. However, only 3% fruit damage occurred in plots treated with esfenvalerate. These results suggest that larvae in the commercial apple orchards in western New York are resistant to azinphosmethyl and chlorpyrifos. Despite the 5.2-fold resistance level recorded for esfenvalerate, field applications of this insecticide still provide commercially acceptable control.