Effects of soybean row spacing on spray penetration and efficacy of insecticides applied with aerial and ground equipment

Kromecote) or water-sensitive cards were placed at three or four vertical levels within the canopy of wide (96.5-101.1 cm) and narrow (17.8-25.4 cm) rows of soybeans, Glycine max to measure spray penetration and droplet characteristics of insecticides applied with aerial or ground equipment. Larval mortality data were used to measure the efficacy of the insecticides at three vertical strata within the two row-spacing systems. The size of the droplets deposited was generally smaller within all levels of the narrow-row canopy compared to the wide-row canopy. The variable combination of drops per cm super(2) and number median diameter was significantly correlated with the percentage of reductions of lepidopterous larval populations of the soybean looper. Pseudoplusia includens) (Walker), velvetbean caterpillar, Anticarsia gemmatalis Huebner, and green cloverworm, Plathypena scabra (Fab.).