Natural occurrence of Beauveria bassiana on adults of the invasive mango seed weevil Sternochetus mangiferae (Coleoptera: Curculionidae) in Brazil

The mango seed weevil Sternochetus mangiferae (Fabricius) (Coleoptera: Curculionidae) was detected in Brazil in 2014, becoming a potential threat to mango production and fruit exports. Efforts have been made to mitigate the spread of this invasive pest in the country, and alternative control strategies, including the search for natural enemies, have been considered, because the pest is still found locally established. This is the first report of a naturally occurring fungal disease in populations of this invasive pest in Brazil. Adults colonized by the fungus in areas with a historical background of infestation were found attached to the tree trunk or on the ground during 2017 and 2019. Through phylogenetic analyses, all collected fungal strains were identified as Beauveria bassiana. Between 10.4 and 60.4% of the adults exposed to conidial suspensions (1 × 108 conidia.mL−1) of S. mangiferae-derived isolates in laboratory bioassays were killed after 13 days. B. bassiana strains registered as biopesticides in the country induced higher levels of mortality (66.7–95.8%) using the same concentration and after the same period. New delivery strategies of selected B. bassiana strains that consider the insect behavior should be further investigated and seen as a safer alternative to reduce populations of this invasive pest.