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Bees Employed as Flying Doctors

University of Adelaide researchers are using bees to deliver a biological control agent that prevents brown rot in cherries.

“Brown rot is caused by a fungus,” explains project leader Dr Katja Hogendoorn. “All commercial cherry growers spray [fungicide] during flowering to control the later development of cherry brown rot.

“Instead of spraying fungicide, we’re using bees to deliver a biological control agent right to the flowers where it is needed. This uses an innovative delivery method called entomovectoring.”

The biological control agent contains the spores of a parasitic fungus that prevents the brown rot fungus from colonising the flower. Every morning, the cherry grower sprinkles the spores into a specially designed dispenser that has been fitted in front of the hive. The bees pick up the spores between their body hairs and bring them to the flowers.

“The ‘flying doctors’ technology is used successfully in Europe to control strawberry grey mould, but it’s the first time for Australia and the first time in cherry orchards anywhere,” Hogendoorn says.

Hogendoorn says the use of bees has many environmental and economic benefits compared with spraying fungicide. “The bees deliver control on target, every day,” she says. “There is no spray drift or run-off into the environment, less use of heavy equipment, water, labour and fuel.”

Hogendoorn says adoption of the technique will have the additional benefit of building up the honey bee industry and the number of managed hives. This will help prepare Australia for the expected incursion of the Varroa mite, which is causing great damage and cost to bee and horticultural industries around the world.

With increasing availability of suitable biological control agents, future application of entomovectoring is expected to become available for disease control in almonds, grapes, strawberries, raspberries, apples, pears and stone fruit.