Aerial, ground and chemigation spray deposition on corn for the control of spodoptera frugiperda (lepidoptera: noctuidae)

Abstract

Pesticides can be applied by aircraft, ground-sprayers or sprinkler irrigation. However, selecting the best option is complicated by the limited number of studies comparing these techniques. Thus, the objective of this work was to study the chlorpyrifos insecticide deposition applied by aircraft (30 L ha-1), tractor-mounted sprayer (200 L ha-1) and chemigation (70,000 L ha-1) for the control of Spodoptera frugiperda (J.E. Smith) in two corn (Zea mays L.) populations (70,000 and 100,000 plants ha-1). Active ingredient residue on the corn plant leaves was evaluated by gas chromatography, immediately and ten days after the treatments. Armyworm numbers in each plot and control were also evaluated. The experiment was set up in randomized blocks with four replications. Aerial and ground applications of chlorpyrifos led to greater active ingredient deposition in the leaves than chemigation. Neither plant population (70,000 and 100,000 plants ha-1) affected the insecticide deposition in the corn leaves. S. frugiperda control was similar for all three application methods. Chemigation, however, resulted in less deposition on the plants and consequently in a greater insecticide loss to the soil, which should be considered in environmental impact.