Action Thresholds for Green Peach Aphid on Potatoes in Minnesota12

Abstract

The appropriate action threshold for application of insecticidal sprays to control green peach aphid, Myzus persicae (Sulzer), on potatoes, Solanum tuberosum (L.), appeared to be ca. 30 apterae/105 leaves. For seed production, assuming a soil systemic was used at planting, an action threshold of ca. 10 apterae/105 leaves was indicated. Spraying on a schedule, even with effective aphicides, can result in late-season green peach aphid control problems more severe than occur on untreated potatoes. Serious outbreaks resulted when an insecticide to which the aphid is resistant was applied on a schedule. During this study, 2 insecticides, pirimicarb and fenvalerate, lost much of their original effectiveness against green peach aphid.