【Objective】The objective of the current study was to elucidate the control efficacy of 2.2% emamectin benzoate ME against rice stem borer（Chilo suppressalis）， and the duration of its effectiveness， for effectively controlling the rice stem borer. 【Method】Rice plants were sprayed with 2.2% emamectin benzoate ME （10，20，30 ga.i./ha）， 5% fipronil SC （30 ga.i./ha) and 20% triazophos EC （400 ga.i./ha） at the peak stage of egg hatching in rice stem borer. Spray of water was used as control. The first and second generations of rice stem borer were chosen as the control targets of a new biological pesticide emamectin benzoate 2.2% ME. Rate of dead heart panicle and seedling protection effect of pesticides on rice were investigated on appearance of significant disease symptoms. The phytotoxicity of emamectin benzoate on rice and be-
neficial species was also observed. 【Result】The results showed that the damage of rice stem borer was effectively and persistently controlled by emamectin benzoate 2.2% ME. The seedling protection and insecticidal effect were ranged between 90-100% and 92-100%， respectively， at 36 d after application for controlling the first generation of rice stem borer. In case of second generation of rice stem borer， the rate of white panicle and damaged plant were controlled at 0.3-1.2% and 0.2-1.8%， respectively， with the control efficiency of 85.0-98.0%. Any detrimental effects were not observed on rice， other beneficial insect species or the aquatic organisms， after spraying 2.2% emamectin benzoate ME. 【Conclusion】2.2% emamectin benzoate ME was found to effectively control the rice stem borers for long duration. Its spray at 15-30 ga.i./ha concentration during the peak incidences of adult borers was recommended for controlling rice stem borer effectively.