Codling Moth: Control on Pears with Diflubenzuron and Effects on Nontarget Pest and Beneficial Species13

Diflubenzuron was evaluated in southern Oregon pear orchards for control of the codling moth, Laspeyresia pomonella (L.), and for effects on nontarget species. Diflubenzuron was most effective when the 1st summer treatment was timed to coincide with 1st moth flight in the late spring. Increased rates of diflubenzuron improved codling moth control but were more disruptive than lower rates to natural enemies of the pear psylla, Psylla pyricola Foerster. Diflubenzuron used at 0.14 kg AI/ha caused no reduction in psylla natural enemies compared to densities in untreated checks. Pear psylla levels were 3- to 4-fold higher in standard treatments with azinphosmethyl or phosmet compared to those in diflubenzuron plots. This was attributed to the reduction in natural enemies found in the organophosphate control program. No increase in two spotted spider mite, Tetranychus urticae Koch, densities was noted following diflubenzuron treatments compared to the untreated check plot.