Sterile males of Ceratitis capitata (Diptera: Tephritidae) as disseminators of Beauveria bassiana conidia for IPM strategies

Abstract

Sterile Mediterranean fruit fly, Ceratitis capitata (Wied.), males were evaluated as vectors to spread Beauveria bassiana (Bals) conidia to wild C. capitata populations under field conditions. The inoculated sterile males were released by air, using the chilled adult technique over 7000 ha of coffee growing in Chimaltenango, Guatemala, Central America. The impact of releases was determined using dry traps baited with a food attractant. The effects of these releases on Apis mellifera, Linnaeus (honey bee), Hypothenemus hampei, Ferrari (coffee berry borer) and the parasitic mite Varroa destructor (Oudeman) were also evaluated. Inoculated sterile males were able to transmit fungal spores to 44% of the wild C. capitata flies captured in traps, which likely were infected through intra- and intersexual interactions during leks, mating or mating attempts. There was no transmission of the fungal spores to non-target insect species such as coffee berry borer, honey bees or varroa. We conclude that sterile males of Mediterranean fruit fly inoculated with B. bassiana can act as effective vectors of conidia to wild populations, constituting a safe, environmentally friendly and selective alternative for suppressing the medfly under a Sterile Insect Technique-based IPM approach.

Keywords:

• sterile insect technique
• vector
• fungi
• horizontal transmission
• pest suppression
• beneficial insects

Acknowledgements

The authors are thankful to Dr. David Midgarden (IS-APHIS-USDA) for helpful revision of a previous version of the manuscript. We also thank Emidgio Espinoza, Enoc Gomez, Eric Lopez, Rony Rodas and the staff of the Field Operation Center of the Central Highlands, Guatemala Medfly Program, as well as Jorge Ibarra and the staff of the Beekeeping Program Salama, Medfly Program, Guatemala for their helpful technical assistance. To Ervin Trujillo and staff whose constructed the device for inoculation of sterile males. We also thank Oscar Campos from ANACAFE for his guidance and the Moscamed Regional Program for logistical support.