Characterization of á-amylase in the alimentary canal of Naranga aenescens Moore (Lepidoptera: Noctuidae), the Rice green caterpillarAbstract : The á-amylases in whole gut of Naranga aenescens (Lepidoptera: Noctuidea) were isolated and characterized by using spectrophotometrically assays. The results showed the existence of the enzyme with a high activity in the gut so that the optimal pH and temperature were evaluated 10 and 30 °C, respectively. The activity of á-amylase was inhibited by NaCl and CaCl2 and increased or remained no effect by other used compounds. Determination of the band on the Native-PAGE electrophoresis showed a single isozyme of á-amylase in the gut N. aenescens. Study on digestive enzymes of insects is one of the new and winning area to reach a safe and effective way to decrease the damages of the pest on agricultural products. Also, determination of different specific inhibitors are necessary to reach a real and reliant results.