Efficacy of insecticides applied to soybean seeds in controlling Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) under two soil moisture conditions

Resumo

The present work aimed to evaluate the effectiveness of insecticides applied to soybean seeds aiming to control Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) caterpillars in two soil water conditions. In the 7-day post-emergence assessment (DAE), the fipronil and thiamethoxam treatments provided the highest percentages of control of S. frugiperda caterpillars and lower levels of soybean defoliation at 70% FC. At 14 DAE, the highest percentages of caterpillar control and the lowest percentages of soybean defoliation were observed with the insecticide chlorantraniliprole and with the thiamethoxam + cyantraniliprole mixture. In the last two evaluations of the trial, the treatments fipronil and thiamethoxam presented the 21 DAE with higher levels of caterpillar control and lower percentages of soybean defoliation in the condition of 70 % FC. At 28 DAE. the fipronil and thiamethoxam treatments and the imidacloprid + thiodicarb mixture showed higher levels of caterpillar mortality and lower levels of soybean defoliation also in the70% FC. It was concluded that the chemical treatments chlorantraniliprole and thiamethoxam + cyantraniliprole were the most effective in controlling S. frugiperda caterpillars, regardless of the level of moisture present in the soil.