Suppressing effect of gamma-irradiated weevils on progeny production in the West Indian sweetpotato weevil Euscepes postfasciatus (Coleoptera: Curculionidae)

Abstract

The West Indian sweet potato weevil Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae) is a major pest of sweet potato Ipomoea batatas (L.) in the tropical and subtropical regions. The sterile insect technique (SIT) could be used as one of the most effective methods for suppression or eradication of the weevil. The effectiveness of SIT depends on the ability of the released sterile males to mate with and inseminate wild females. However, the effect of sterile weevils on the fitness of E. postfasciatus has not been evaluated on natural density. Here, we investigated the effect of gamma-irradiated weevil density on the number of weevil progeny. When irradiated weevils were released in numbers equal to those of non-irradiated weevils, the number of progeny was reduced by half of that in the control treatment, and it remained at this state for 2 weeks. Our results show that irradiated weevils ensure adequate and efficient suppression of wild weevils. We conclude that the SIT programs will be employed as effective eradication method for E. postfasciatus.