Simultaneous use of SIT plus disseminator devices of Beauveria bassiana enhances horizontal transmission in Anastrepha ludens

Beauveria bassiana is an entomopathogenic fungus widely used to control different insect pests including Anastrepha ludens (Diptera: Tephritidae), a key pest of citrus and mangoes. Currently, to control this pest, sterile A. ludens males of the Tap-7 genetic sexing strain are released weekly by aircraft at a density of 1,000 males/ha as part of an integrated pest management programme (IPM) in Southern Mexico. Our objective here was to determine whether the sterile insect technique (SIT) could be enhanced by augmenting it with horizontal transmission of fungus conidia by using Beauveria bassiana disseminator devices (DBb) designed to distribute it with minimal impact on non-target species. Four treatments were established: DBb only, DBb + SIT, SIT only and untreated control, and fruit fly populations were monitored using two Multilure traps baited with 250 ml of CeraTrap per plot. We found that the presence of B. bassiana disseminator devices in areas where A. ludens sterile males were released resulted in higher proportions of infected wild fruit flies in the field, and that high relative humidity (rainy season) played an important role in the efficiency of horizontal conidia transmission to the wild populations. We conclude that the simultaneous use of both strategies (SIT + DBb) increases the conidia transmission to wild populations, and that this approach could be incorporated to an integrated pest management for the better suppression of fruit fly populations.