Sterilization of adult fall armyworms by gamma irradiation and its effect on competitiveness

The quantity of 00CO irradiation necessary to sterilize adult male Spodoptera frugiperda (J. E. Smith) was established at 35 krad, while a dose of 15 krad sterilized the female. In laboratory and field tests, sterilizing doses did not alter the lifespan of the adults, ability of the female to attract the male, ability of the male to seek the female, or ability of the adults to copulate. However, sterilization significantly reduced the oviposition rate of sterile females and the type and quality of sperm transferred by sterile males. These adverse effects were reflected in reduced egg hatch. The data indicate that sterilized males are approximately 0.46 times as competitive as normal males.