Impact of Fenvalerate and Diflubenzuron on Target and Nontarget Arthropod Species on Bartlett Pears in Northern California

Publisher Website
Google Scholar
Abstract
The synthetic pyrethroid fenvalerate provided commercial control of the pear psylla, Psylla pyricola Foerster, during the prebloom as well as the foliar period. Two cover sprays at 6.7 and 13.5 g AI/100 liters gave seasonal control. This compound was equally effective against the codling moth, Laspeyresia pomonella (L.), at rates ranging from 3.4 to 13.5 g AI/100 liters. Even a single well-timed 1st cover spray gave acceptable seasonal protection. All foliar applications of fenvalerate resulted in increased populations of spider mites, primarily the twosponed spider mite, Tetranychus urticae Koch, even though higher dosages were initially somewhat acaricidal. Peak levels of spider mites during the summer were correlated with the amount of foliage present at the time of pyrethroid application. Apparently regulation of spider mites by natural enemies became decreasingly poorer as less pesticide-free leaf surface was available. Fenvalerate at 13.5 g AI/100 liters temporarily suppressed the pear rust mite, Epitrimerus pyri (Nalepa), and did not induce outbreaks of this species. In comparison, diflubenzuron was weaker for codling moth, had no direct effect on pear psylla, but did not induce phytophagous mites.

This publication has 0 references indexed in Scilit: