Efficiency of parasitoid application and the sterile insect technique for the control of Ceratitis capitata: Field cage experiment in the Tulum Valley, San Juan, Argentina

Abstract

Biological control using parasitoid wasps and the sterile insect technique, which involves the release of sterilized male pests, are environmentally sustainable strategies that can be integrated into fruit fly management programs. Both biorational techniques have been applied independently against the invasive pest Ceratitis capitata (Wiedemann), commonly known as the Mediterranean fruit fly, in fruit-growing areas of San Juan Province, central-western Argentina. At the San Juan Biofactory, both sterile males of C. capitata and the exotic parasitoid Diachasmimorpha longicaudata (Ashmead) are mass-reared using the Vienna-8 temperature-sensitive lethal (tsl) genetic sexing strain. The aim of this study was to assess the effectiveness of combining D. longicaudata with sterile medfly males for the control of C. capitata under field-cage conditions. Trials were conducted during the 2019 summer, from January 31 to April 26, at a fruit farm in the Rawson district of San Juan. Each cylindrical iron cage (1 m in diameter, 2 m in height, covered with voile) contained five exposure devices, each holding three semi-ripe figs used as oviposition substrates. The experimental treatments were: (1) control (no release of parasitoids or sterile flies), (2) parasitoid release alone (fertile medflies of a biparental line were released first, followed by parasitoids), (3) sterile fly release alone (fertile flies and sterile males released simultaneously), and (4) combined techniques (fertile and sterile medflies released first, followed by parasitoids). The resulting dataset includes the number of pupae, adult flies, adult parasitoids, as well as the benefit and Abbott’s efficiency for each treatment and experimental condition.