“It is difficult to think how a bee could be more useful.” This sentence begins an article in the September 28, 2000 edition of The Economist magazine. The honey bees’ incredible utility may be intuitively obvious for beekeepers, but not for everyone it seems. According to the article, Scientists at Cornell University in New York state have created and patented a honey bee “footbath” that uses the insects to disperse beneficial micro-organisms to strawberry flowers .
“Strawberries, along with many other soft fruits, suffer from grey mould, a troublesome rotting disease. Although the fungus mainly damages the fruit, infections actually start in the flowers. One effective treatment is to spray those flowers with another fungus called Trichoderma harzanium. This organism competes with the grey mould in flowers, thus eliminating it before the berries form, but causes no harm to the fruit itself.
“Dr Kovach’s system works by putting spores of Trichoderma into a specially designed tray. This is encased inside a plastic housing which is then fixed into the entrance of a hive. That means that the tray can be removed and replaced as easily as a tray of photocopier toner. Bees pick up the spores on their legs as they walk out of the hive, and deposit them on to flowers they visit as they search for pollen and nectar.
“The researchers say that bee-delivery is nearly twice as effective as spraying the spores around by conventional methods, and uses a fraction of the quantity of spores because the insects deliver them directly to the blooms rather than wasting them on the leaves, stems and ground. The result, they claim, is that bee-delivered Trichoderma offers as much protection as the chemical fungicides prefered by most strawberry farmers. And an added bonus is that simply adding a beehive to a field of strawberries improves yields by 20-30%, because of better pollination.
“Dr. Kovach has high hopes for extending the use of his system. Not only is it likely to be effective with other fruit, such as raspberries; it could also be filled with other biological-control agents, such as beneficial bacteria and viruses, which separate studies have shown that bees can also deliver. Indeed, according to Dr Kovach, the system could be used to “vaccinate” plants against disease as well as treating them. A group of newly discovered chemicals that can stimulate a plant’s immune system to resist infection would be eminently deliverable by bees.
“Bee lovers around the world need not be concerned, however. The actual payload carried by the insects is very small, and their fungal footbath has no effect on their health. Honey lovers need not worry either. Trichoderma is found naturally on strawberry flowers, and in any case the honey produced during strawberry-bloom time is eaten by the bees themselves; the stuff harvested for human consumption is made much later in the year.
“The system does have a couple of drawbacks. Bees will fly about only in good weather, so if your crop blooms on a rainy day, too bad. And bees are fickle. Although they can be trained to feed on a particular crop, if they find a sweeter, more delectable flower nearby they will be tempted away to new pastures.” The article concludes, therefore, that although a good idea, it is not necessarily the bee all and end all. Biological control never is, however, whether in berries or honey bees themselves.
