The outbreak of armyworm is uncertain and causing substantial yield loss in rice. Hence, an action research was carried out to evaluate the efficacy of different management treatments as, i) Emamectin benzoate 5 SG @ 0.3 gm/lit; ii) Cypermethrin 25 EC @ 1ml/lit; iii) Fenvalerate 20 EC @ 1 ml/lit; and iv. Untreated check against two armyworm species namely, Mythimna separata (Walker) and Spodoptera litura (Fabricius) during outbreak in rice field of Piple, Chitwan in October, 2013. The experiment was laid out in randomized complete block design with five replications. The efficacy study revealed that all treatments significantly reduced larval population and increased grain yield over untreated check (p<0.05). There was highest population reduction in Emamectin benzoate treated plots (90.24%) followed by Fenvalerate (79.31%) and Cypermethrin (70.77%). The significantly highest grain yield was obtained in Emamectin benzoate treated plots (2.01 mt/ha) followed by Cypermethrin (1.47 mt/ha), Fenvalerate (1.44 mt/ha) and untreated check (0.96 mt/ha). Increase in grain yield over untreated check was observed highest in Emamectin benzoate treated plots (90.24%) followed by Fenvalerate (79.31%) and Cypermethrin (70.77%). From this study, it was concluded that Emamectin benzoate is the most viable option for armyworm outbreak management.
