Laboratory evaluation of 15 entomopathogenic fungal spore formulations on the mortality of Drosophila suzukii (Diptera: Drosophilidae), related drosophilids, and honeybees

Abstract

Abstract The drosophilids Drosophila suzukii (Matsumura), Drosophila melanogaster Meigen and Zaprionus indianus Gupta (Diptera: Drosophilidae), are common pests of Mexican berry plantations. Attract-and-infect-based application strategies using entomopathogenic fungi (EPF), which are more environmentally friendly than synthetic chemical pesticides, are currently under evaluation for their potential at controlling insect pests, as compared to synthetic pesticides. In this study, we evaluated 15 EPF formulations against D. suzukii adults to determine which formulations would work best in an attract-and-infect device in terms of spore accumulation, pathogenicity, and mortality. Formulations of Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae), Cordyceps javanica (Friederichs & Bally) (Hypocreales: Cordycipitaceae), and Metarhizium anisopliae (Metschnikoff) Sorokin (Hypocreales: Clavicipitaceae) spores exhibited the highest levels of conidia attachment, pathogenicity, and virulence, making them effective against D. suzukii. In a subsequent experiment, these formulations were evaluated against D. melanogaster, Z. indianus, and the honey bee, Apis mellifera L. (Hymenoptera: Apidae). Our results revealed that the formulations containing C. javanica and M. anisopliae were highly virulent not only against D. suzukii, but also against D. melanogaster and Z. indianus, with minimal impact on honey bees. Our results showed that spore formulations of M. anisopliae and C. javanica were the most promising entomopathogens for further testing of attract-and-infect devices to manage D. suzukii, D. melanogaster and Z. indianus in berry crops.