COLUMBUS, Ohio - Researchers from Ohio State and Cornell universities have found that bees can deliver a biological fungicide to strawberry blooms more effectively than can mechanical sprayers.
The study involved placing a tray filled with the fungicide - composed of an anti-fungal microorganism - in front of bee hives. The bees walk through this "foot bath" while exiting the hive and deposit the fungicide on strawberry flowers.
Using the procedure to dispense a natural fungicide that prevents gray mold - a common rotting disease in strawberries - researchers were able to reduce infected strawberries by 72 percent as compared to 40 percent when the same fungicide was sprayed on plants.
The bee-delivered natural fungicide was also as effective at preventing gray mold as a commercially available chemical fungicide that was sprayed on plants. "Since bees carry the fungicide specifically to the flowers, they are more effective than sprays," said
Joseph Kovach, associate professor of entomology at Ohio State's Ohio Agricultural Research and Development Center in Wooster, Ohio. "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. He and his Cornell colleagues tested the procedure on 12 strawberry fields in New York under the state's Integrated Pest Management (IPM) Program. 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.