Methylamine avermactine (Radical) is a novel semi-synthetic derivative of natural product abamactin in avermactin family. The efficiency of this bioinsecticide was evaluated on the adults of S. oryzae . Five concentrations were tested to control the weevil adults. Concentration 0.3 and 0.1 ppm produced weevil mortality as high as 100 % after 8 days, while only 60 and 48.7% mortality was recorded for the same concentration after 4 days. The present study was investigated the effects of Methylamine avermactine on the oxidative stress indicator, and antioxidant enzyme [superoxide dismutase (SOD)] activity in Sitophilus oryzae tissues. There were statistically significant increases in SOD activities in the LC50/48h concentration of Methylamine avermactine -treated Sitophilus oryzae compared to the control. These results indicated that Methylamine avermactine causes an increase in oxidative stress and we conclude that increasing oxidative stress induces antioxidant defense mechanisms.