This study was conducted to evaluate the effect of insecticides on control of Spodoptera exigua, growth characteristics, and dry root yield in the cultivation of Alisma plantago after early maturing rice cropping. All pesticides treated had no effect on growth and flowering rate of Alisma plantago. The major insecticides were teflubenzuron Wp, 5%, tebufenozide Wp, 8%, iufenuron Ec, 5%, and tebufenozide Wp, 5%. Dry root yield were increased largely with tebufenozide Wp, 5%(20 g/20 l), insecticide than the other insecticides and no control. All insecticides had no injury with standard dosage. On the other hand, all insecticides had slight injury in the double dosage level for the Alisma plantago.