How to BEE-come a plant doctor! A new technique developed in Adelaide uses bees to deliver fungal disease control to cherry orchards.
The University of Adelaide researchers have introduced a world first for cherry orchards in Australia. Researchers have come up with a new technique to use bees to deliver disease control to cherry blossoms, preventing brown rot in cherries.
After being successfully implemented in Europe to control strawberry grey mould, it’s the first time in Australia this ‘flying doctor’ technology has been used in cherry orchards anywhere.
This could radically help reduce costs for orchard growers. Annually, the Australian cherry industry loses about $150 million through applying fungicide, yield loss and fruit spoilage according to bee researcher Dr. Katja Hogendoorn, a postdoctoral research associate with UA’s School of Agriculture, Food and Wine.
Every morning, the cherry grower sprinkles a biological control agent containing spores of a parasitic fungus that prevents the brown rot fungus from colonising the flower. The spores are placed 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.
Dr. Hogendoorn says the use of bees has many environmental and economic benefits compared to spraying fungicide. She says:
“The bees deliver control on target, every day. There is no spray drift or run-off into the environment, less use of heavy equipment, water, labour and fuel.”
This technique also has the additional benefit of building up the honeybee industry and the number of managed hives. By utilising bees in this way it will help Australia prepare for an expected invasion of the Varroa mite, which is causing great damage and cost to bee and horticultural industries around the world.
Brown rot (Monilinia laxa and Monilinia fructigena) is a fungal disease of apples, pears, plums, cherries and other fruit and ornamental trees, causing a brown, spreading rot in fruit that can devastate the crop. The first symptoms are often seen in spring with dying blossoms that turn to mush and a mass of greyish, fuzzy spores on branches.
Fruit becomes infected through wounds, especially those caused by birds. Affected fruits mummify and may remain hanging on the tree and where they touch the bark they cause small infections (cankers). The fungus remains in the dead fruit and cankers over winter and releases spores in the spring to cause the blossom wilt phase of the disease. These infections in turn release spores to infect wounded fruit.
Until now the best non-chemical control minimised the spread of the pathogens by removing and burying all brown rotted fruit and pruning off and burning infected spurs and blossoms. Fungicides applied for other purposes, such as scab control, may give some incidental control although manufacturers do not claim this.
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