Propagule production of regional entomopathogenic fungi against Drosophila suzukii , an emerging fruit pest in southern Chile

Abstract

Background: Berry crops in Southern Chile with a temperate humid climate are threatened by emerging invasive Drosophila suzukii, and there is urgent need to provide efficient tools for integrated control of this pest. Objective: This study aims to compare the potential of selected entomopathogenic Beauveria bassiana and Metarhizium spp. strains to produce fungal propagules and new conidia on microsclerotia. Materials: Strains isolated from soil samples collected in affected berry plantations and highly virulent against D. suzukii were tested in standard culture conditions, and conidial production on microsclerotia determined at 15°C and 25°C. Results: The capacities to produce conidia, microsclerotia and blastospores depended on strains. The lower temperature did not affect conidial production on microsclerotia. Conclusions: There are promising candidates for the immediate development of a specific mycoinsecticide with the most appropriate propagule; ability of microsclerotia to produce high numbers of conidia in lower temperature encourages the search for innovative formulations to control D. suzukii in Southern Chile.