Interaction Between Spray Distribution and Systemic Activity of Insecticides for Control of European Corn Borer (Lepidoptera: Pyralidae) in Peppers and Snap Beans

Abstract

Interactions between spray distribution and insecticide mode of action in relation to control of European corn borer, Ostrinia nubilalis (Hubner), on bell peppers ( Capsicum annuum L.), sweet banana peppers ( Capsicum annuum L.), and snap beans ( Phaseolus vulgaris L.) were investigated. Multiple treatments were applied using either a conventional boom sprayer or an air-curtain sprayer. Materials evaluated were fenvalerate (local activity) and acephate (systemic activity). Spray droplet distribution was evaluated with UV-spectrophotometric analysis of sprayed dyes. European corn borer egg massey were sampled weekly during the experiment, and crop injury was evaluated at harvest. Spray deposition with the air-curtain sprayer was much higher on the undersides of the leaves and on fruit than with the conventional boom application. Variability of spray deposition between samples also was reduced. Faceplate and fenvalerate significantly reduced banana pepper and bell pepper injury from European corn borer. However, significant reductions in injury due to air-curtain application occurred only with fenvalerate on bell peppers. Systemic activity of the acephate compensated, at least partially, for poor spray distribution with the conventional boom application. Virtually no injury occurred to the snap beans even in artificially infested, untreated plots. Total mortality caused by glandular trichomes was observed when larvae were introduced onto snap bean plants in the laboratory.