Impact of acquired entomopathogenic fungi on adult Drosophila suzukii survival and fecundity

Exposure of Drosophila suzukii adults to surfaces treated with Metarhizium brunneum, Beauveria bassiana, Isaria fumosorosea or Lecanicillium lecanii conidia under laboratory conditions resulted in fly infection and dose dependent mortality. Scanning electron microscopy confirmed that conidia accumulated on D. suzukii pretarsi after <= 48 h exposure to the dried conidia treated surfaces. Approximately 50% of the flies died post exposure to 1 x 10(8) conidia of each isolate distributed over approximately 148 cm(2) by 7, 10, 12 and 13 days respectively at 25 degrees C. Temperature had an impact on fungus-induced D. suzukii mortality when tested at 20, 25 and 30 degrees C, although control mortality was also significant at 30 degrees C. Fifty percent of the control D. suzukii adults died after being held at 30 degrees C for 11-13 days. Significantly lower oviposition, recorded as F1 pupae, was recorded from adult D. suzukii exposed to M. brunneum compared to the number of offspring produced by control flies indicating that the fungus had a negative impact on fly fecundity. Evidence of transmission of acquired M. brunneum conidia between sexes was recorded. Crown Copyright (C) 2016 Published by Elsevier Inc. All rights reserved.