Evaluation of bee-vectored Aureobasidium pullulans for biocontrol of grey mould in strawberry

Sammanfattning: The fungal pathogen Botrytis cinerea causes grey mould in strawberry (Fragaria x ananassa) inflicting great yield loss and significant economic loss. To date, spraying with chemical fungicides is the primary management practice to control this disease. Concerns regarding resistance development of the pathogen, high treatment cost and environmental issues have led to the search for alternative methods. This study investigates if the biocontrol fungus Aureobasidium pullulans (isolate AP-SLU6) could be used as a biocontrol agent vectored by buff-tailed bumblebee, to suppress grey mould in strawberry under greenhouse conditions. To examine if A. pullulans affect bumblebees negatively, trials measuring the flight activity and the hive weight was performed. To test if the bees can carry and deposit the biocontrol agent to strawberry flowers, samples of flowers and bumblebees were collected and examined. Finally, the scoring of grey mould infection on fruits was performed pre-and postharvest. Bee activity and hive weight was not significantly affected by the carried fungal biocontrol agent. The results further showed that bumblebees successfully vectored the biocontrol agent to flowers and significantly reduced the severity of grey mould infected fruits during postharvest storage, thus leading to improved shelf life. This study concludes that A. pullulans used as a biocontrol agent vectored by bumblebees, can be an efficient method for controlling postharvest grey mould in strawberry, leading to improved plant health and reduced dependence on synthetic fungicides.