The fall armyworm (Spodoptera frugiperda) is an important insect pest of maize, being frequently controlled through the use of insecticides. In the counties of Cruz Alta, Fortaleza dos Valos and Pejuçara, Rio Grande do Sul State, there have been reports of low insecticide efficiency. Three field experiments were conducted including different application methods, timing and volume of insecticides. The evaluation was based on number of live and dead larvae per plant at four and eight days after treatment. The results showed that the efficiency of insecticides varied with the application method and timing, as well as with the volume of suspension applied. Lower insecticide efficacy was observed for late application (when damage was severe), for the method of application on total surface area and using smaller volume of suspension (150l/ha). Increased insecticide control was observed when they were applied at the beggining of insect attack and directing the spray toward the inside of the plant whorl and with higher suspension volume (300l/ha). The insecticide lufenuron (12.5g a. i./ha), in three field experiments, provided high insect control.
Insecta; pest control; insecticides; application methods
