LAUSR

Grey mould caused by Botrytis cinerea is a common post-harvest disease in strawberries, reducing shelf life considerably. We investigated the potential of the yeast-like biocontrol fungus Aureobasidium pullulans (AP-SLU6) vectored by bumblebees (Bombus terrestris) in the Flying Doctors® system to inhibit the pathogen and increase the shelf life of harvested strawberries (cv. Sonata). Using bumblebees as vectors of various biocontrol agents is becoming increasingly popular, but any potentially negative effects on bee performance have been under-studied. Our results show that over the 4-week period of the trial the performance and activity of the bees were not negatively affected by A. pullulans. The bees successfully picked up the powder formulation, carried and deposited it on the flowers. The vectoring of the biocontrol agent significantly reduced grey mould development on the harvested fruits by 45 % and increased shelf life by 100 % in comparison to control treatments. This suggests that the biocontrol fungus applied during flowering successfully reduced Botrytis infection and thus effectively protected the fruits from grey mould. In addition, the bee-vectored application of the biocontrol agent was found to be significantly more effective than spray application, since the latter may temporarily increase humidity around the flower, thereby creating a suitable environment for the pathogen to thrive. In summary, our study demonstrates that A. pullulans vectored by bumblebees can decrease grey mould infection and improve the shelf life of strawberries without adversely affecting the bees, thus providing a basis for the sustainable and efficient control of grey mould on strawberry.