First report on the entomopathogenicity and virulence of Akanthomyces muscarius LY 72.14, a Yungas native fungal isolate, for Anastrepha fraterculus control

Abstract

In this work, we report the entomopathogenic potential of Akanthomyces muscarius LY72.14, a fungus isolated from a soil sample collected in the Southernmost sector of Las Yungas (Tucumán, Argentina) subtropical rainforest. The isolated fungus exhibited both pathogenicity and virulence in larvae, pupae and adults of the pestiferous fruit fly Anastrepha fraterculus, ability that could then be applicable for fruit pest biocontrol. Groups of 120 late-third-instar larvae were inoculated by immersion with four different conidial concentrations of A. muscarius LY 72.14 ranging from 105 to 108 conidia mL−1. Mycosis was subsequently verified through different time lapses for larva (1–2 days), pupa (14 days) and adults (13 days). Results revealed adult stage as the most susceptible to fungal infection, with a mortality percentage of 29.4 ± 3.2%, whilst pupal mortality reached 7.8 ± 1.2%. On the other hand, larval mortality was similar to the non-infected control (5.9 ± 1.4%). When 108 conidia mL−1 fungal inocula were used, the total host mortality (involving the three fly developmental stages) reached 53%. Virulence against fly adults was significantly dependent on high conidial concentrations, achieving a LC50 value of 8.4 × 107 conidia mL−1, with a similar killing effectiveness pattern (43–45%) among 107 and 108 conidial concentrations. The promising herein demonstrated biocontrol potential of A. muscarius LY 72.14 to effectively infect and kill A. fraterculus under lab-condition assays, makes relevant to evaluate this native fungal isolate under field-cage and open-field conditions to weight the possibilities for biocontrol massive usage and its tentative application for integrated plague management.