Behavioural response of the fungus gnat,Bradysia impatiens (Diptera: Sciaridae) towards certain edible mushrooms and saprophytic fungi

The fungus gnat Bradysia impatiens (Johannsen) is a worldwide pest inhabiting organic-rich environments, including mushroom-cultivation substrates, which leads to massive production losses of edible mushrooms. To promote a non-insecticidal pest control strategy, we evaluated adult behavioural response towards two saprophytic fungal strains Aspergillus flavus Link and Mucor circinelloides Tiegh., isolated from B. impatiens-inhabiting substrates and six edible mushrooms species. Our results indicated that (a) B. impatiens was most attracted to the oyster mushroom Pleurotus ostreatus among all six edible mushrooms; (b) males and females demonstrated a significant attraction for M. circinelloides over A. flavus and P. ostreatus; (c) adults demonstrated dynamic attraction tendencies that varied with the culture periods of A. flavus and M. circinelloides, wherein females represented most (mean = 78.6%) of the attracted individuals; and (d) larvae that fed on mycelial cultures of M. circinelloides could complete their entire life cycles, but larvae could not survive on a non-fungal or A. flavus diet. These results demonstrate the potential for the development of M. circinelloides in a push-pull strategy to biocontrol this pest in edible mushroom cultivation.