Friend and foe: blueberry pollinators as mummy berry vectors

Mummy berry, (Monilinia vaccinii-corymbosi) is an important fungal pathogen of blueberries. Mummy berry relies on insect pollinators to move spores from infected leaves to flowers. A novel research technique using digital video recorders (DVRs) and video cameras was developed to investigate the pollinator-pathogen interactions of mummy berry in blueberries. Video cameras were set up in each of three southeast Michigan blueberry fields during spring 2008 and 2009 an focused on: shoot strikes (source of mummy berry secondary spores), flowers, and healthy leaves. More than 10,000 hours of video footage was recorded in the field, and then reviewed and analyzed in the laboratory. Insects in the video clips were identified to “morpho” species, and behavior was categorized (i.e. approach, contact, or feed) and quantified. Flowers had the highest number of insect interactions and shoot strikes had the greater diversity of visitors. Bees contacted shoot strikes in 3% of interactions and flowers in 68% of interactions. Flies contacted shoot strikes in 49% of interactions and flowers in 28% of interactions. These data suggest that flies, rather than bees, may be more likely to vector mummy berry. However, flies may also be providing valuable pollination services.