GPA-Cast, a Computer Forecasting System for Predicting Populations and Implementing Control of the Green Peach Aphid on Potatoes 2

Abstract

Three yr of field observations of the interaction of aldicarb, a systemic insecticide, green peach aphids (GPA), and GPA natural enemies were used to develop a computer forecast system, GPA-CAST. This system was utilized to predict current year field populations of GPA. Predictions showed close agreement with observed field populations until application of the selective aphicide, pirimicarb. Populations of GPA after sprays with pirimicarb were overestimated by GPA-CAST. Since pirimicarb was less toxic to natural enemies than to GPA, overestimation may have been due to continued predation on reduced GPA populations.