Importance of Organophosphate (OP) Insecticides in an IPM-based Peach Orchard Management System

Abstract

The Food Quality Protection Act provides for review of pesticide use on food products providing potentially significant challenges to orchardists. IPM should reduce pesticide use but not fruit quality. This project compares effectiveness of OP and non-OP insecticides used in an IPM peach management program and compares spray program efficiency in commercial peach orchards. OP vs. non-OP insecticide treatments (Guthion and Lorsban vs. Thiodan and Asana) targeting plum curculio (PC) and plant bugs (PB) were applied to 7-year-old `Cresthaven' and `Jayhaven' trees in a split-plot design. Insect damage to fruit samples from commercial orchards was compared to the IPM demonstration orchard. PC insecticide application was based on a threshold of 0.1 PC per trap per day from screen traps. `Jayhaven' and `Cresthaven' trees in the IPM demonstration orchard received three and four insecticide applications, respectively. Total fruit yield was not significantly different between OP and non-OP plots. Total PC damage from `Jayhaven' trees in OP plots was 4.8% compared to 8.2% from non-OP plots. Less than 2% of fruit from `Jayhaven' and `Cresthaven' trees in OP plots contained PC larva compared to >6% from non-OP plots. PB damage to fruit was slightly higher in OP vs. non-OP plots. Insecticide applications in commercial orchards ranged from six to 12, resulting in PC damage ranging from 0% to 8.2%.