Five-to six-day old male pupae of Ectomyelois ceratoniae Zeller were irradiated with 0, 20, 25 and 30 krad of gamma rays. When the radiated males were mated with normal females there were deleterious effects on fertility without extreme effects on mating or fecundity. Percentage of embryonated eggs and progeny per female decreased to two thirds of the control by 25 and 30 krad treatments. Productivity of the female mated with irradiated males was decreased and significant reductions in egg viability, egg hatch and larvae per female were observed in F1 generation. Similar pattern of sterility was observed in sibling crosses of F2 at the three doses.
