[en] Lethal and sterilizing effects of ionizing radiation on a laboratory strain of sitophilus oryzae (L.) were studied. The insects were reared on wheat, variety Giza 155, at 30 degree C and 70% R.H. The developmental stages used were 1 and 3-day old eggs, 1 and 2-weeks old larvae, 3-days old pupae and one week old adults. Results obtained showed that : 1) Adults resulted from irradiated 1 and 3-days old eggs failed to give new progeny the dosage used was 12 Gy 2) Female adults resulting from 1 and 2-weeks old larvae treated at 22.5 Gy were sterile 3) Female adults resulting from treated 3-days old pupae failed to give any progeny when the dose used was 40 Gy 4) Adults were much more tolerant than all other stages 5) A dosage of 72 Gy caused complete sterility to adults, and this dose seems to be reliable for the control of sitophilus oryzae (L.) in infested stored wheat.5 tab