RESUMEN
Results showed that the Flight Ability Index [FAI] of old World Screwworm [OWS] fly chrysomya bezziana adults which emerged from irradiated pupae with 30, 45, 60 and 75 Gy of gamma ray was not affected under lab. conditions but it was effected under field condition. Result of mating competitiveness of adults emerged from irradiated pupae with 30 and 60 Gy of gamma rays and mated as follows: a- Irradiated males: unirradiated males: unirradiated females. b- Irradiated females: unirradiated females: unirradiated males. c- lrradiated females: irradiated males: unirradiated females: unirradiated males. Showed that males irradiated with 30 Gy and mated as in a: reduced and have the percentages of egg hatching and have a very good competitiveness value and this dose which caused complete sterility in C. bezziana had no effect on this parameter, moreover, 30 Gy gamma rays caused an effect to females which mated as in b: Finally the results showed that irradiated males and females with 30 Gy as in c: had a very good mating competitiveness value