WINE lovers could soon be toasting a friendly fungus that protects vines from
a devastating mould without the need for chemical sprays.
The mould Botrytis cinerea feeds on dead plant matter. It also rots
grapes, covering bunches with a powdery grey mould. But now a team of
researchers in New Zealand has discovered a harmless, tasteless fungus that
outcompetes Botrytis for nutrients without damaging the plant or
fruit.
When sprayed on flowers and young grapes, the fungus stops Botrytis
from getting a foothold, says Philip Elmer, who led the team based at government
research institute HortResearch in Hamilton. 鈥淚t鈥檚 not 100 per cent wipe-out,鈥�
says Elmer. 鈥淏ut it very significantly reduces the amount of Botrytis in
the bunch.鈥�
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Botrytis is resistant to many standard treatments, and the only way
to kill it at the moment is to spray vines with expensive, synthetic fungicides.
The researchers hope their natural alternative will combat the crop losses and
reduced quality caused by the mould, which costs the New Zealand wine industry
millions of dollars each year.
Growers dread Botrytis outbreaks because the only way to avoid rotten
grapes is to harvest early, when sugar levels are too low to make good wine.
鈥淒uring hot, humid weather, harvesters can work 24 hours to try to get the
grapes. It鈥檚 almost like a race against the Botrytis,鈥� says team member
Peter Wood.
The identity of the helpful fungus is being kept secret until a patent has
been finalised. It will be marketed as a spray called Botry-Zen by New Zealand
biotech company Zenith Technology. 鈥淚t鈥檚 our aim that it won鈥檛 be any more
expensive than the synthetic fungicides,鈥� says Philip Gregan of the Wine
Institute of New Zealand, which helped fund the research.
But that may not help everyone. 鈥淎 lot of the small growers cannot afford to
be protected, so they have to live with the fear,鈥� says Marc Fermaud from INRA,
the French Institute for Agronomy Research.
White grapes, which are the predominant type grown in New Zealand, are
particularly prone to the rot because their thin skins provide less protection
than the thicker skins of red varieties. But growers of all grape types are
likely to be interested in the new treatment, says Fermaud. Wine makers want to
cut the use of synthetic chemicals in vineyards, because of increasing consumer
concern about residues, but until now there鈥檚 been no organic treatment for
Botrytis.
HortResearch is now working on a yeast that it hopes will scupper
Botrytis when the mould tries to produce new spores. 鈥淪o even if growers get
the timing of the Botry-Zen wrong, this other agent could help if
Botrytis is starting to get away,鈥� says Elmer. He adds that similar methods
could also work on other susceptible crops, such as kiwi fruit, berries and
roses.