The bee-delivered natural fungicide was also as effective at preventing gray mold as a commercially available chemical fungicide that was sprayed on plants.
Sprays cover both leaves and flowers, though the target is only the flowers.
The study appeared in a recent issue of the journal Biological Control. Kovach did the study while he was working at Cornell University. The fungicide they used for preventing gray mold, which is caused by the fungus Botrytis cineria, was a commercially available strain of a microorganism called Trichoderma harzarium 1295-22. The study was conducted from 1994 to 1997, using commercial bumblebee colonies and honeybee hives. Although flowers collected from the plants that received bee-delivered treatment had only half the density of the natural fungicide as compared to those that were sprayed, they showed better fungus control.