Competitiveness of Boll Weevils (Coleoptera: Curculionidae) Sterilized with Low Doses of Fractionated Irradiation

Male boll weevils, Anthonomus grandis Boheman, sterilized with nine fractionated doses totaling 48 gray (Gy) of irradiation successfully competed with normal untreated males for virgin females. The ratios of Smale:Nmale:Nfemale tested were 1:1:1, 5:1:1, 10:1:1, 20:1:1, and 40:1:1. We determined that Smales, collectively, at a 20:1 or 40:1 ratio of Smale:Nmale were 90.8–95.1% as competitive as Nmales. A 40:1:1 ratio of Smale:Nmale:Nfemale resulted in no matings between Nmales and Nfemales alone. There were an average of 1.8 matings when both Nmale and Smales mated with the Nfemale resulting in 99.9% sterility (based on F₁ adult emergence from eggs collected).