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["Joe Hecksel" <jhecksel@voyager.net>]

Forwarded from Viticulture list.

Milk makes wine fine: Dairy sprays protect grapevines from powdery 
mildew.
18 September 2002
CHARLOTTE WESTNEY
http://www.nature.com/nsu/020916/020916-5.html
Milk could be used to make organic wine. Sprayed on grapevines once a
fortnight, milky water seems to control powdery mildew as effectively as
sulphur and copper fungicides, without tainting the grapes' taste.

Peter Crisp of the University of Adelaide in Australia made the 
discovery
during his survey of traditional treatments for the fungus, which 
currently
costs the Australian wine industry A$30 million (US$16 million) a year.

"Most of them did not provide good control," he says, "but milk and whey
stood out."

The fungus can engulf whole grapes, rendering them unfit for 
wine-making.
Sulphur sprays stop powdery mildew growing by interfering with its 
enzymes.
How milk works is not clear, but full-fat seems to work best.

Milk fat or whey protein may feed microorganisms on the vine surface 
that
then compete for space or even consume the mildew spores, says Wayne
Wilcox, a plant pathologist at Cornell University, New York.

"There is definitely something in the treatment, but I would like to see
more data," says Wilcox. He recently visited an Australian vineyard that
was experimenting with milk treatment. "There was a level of disease 
that
some growers would not find acceptable," he warns.

Reducing sulphur treatment is important to organic wine-makers. "Having 
an
organic farm spraying sulphur seems a bit odd," says Will Davenport,
director of UK organic-wine producer Davenport Vineyards. Standard
fungicides can harm the insects and soil bacteria that keep other pests 
down.

However, vegans could not drink milk-treated wine. So Davenport makes
'compost tea' to control the powdery mildew on his farm. This liquid
compost is full of soil bacteria, but contains no fungal spores. Sprayed 
on
a vine, the bacteria cover the plant's leaves, competing with, and 
eating,
the fungal spores.


© Nature News Service / Macmillan Magazines Ltd 2002

-----Suzi Teghtmeyer

Librarian, Paul Evans Library of Fruit Science
Southwest Missouri State University Mtn. Grove Campus and Missouri Fruit
Experiment Station
9740 Red Spring Rd, Mountain Grove, MO 65711
Phone: 417-926-4105, Fax: 417-926-6646,  email: srt175f@smsu.edu
URL: http://library.smsu.edu/paulevans/pelIndex.htm
AgNIC Viticulture site: 
http://library.smsu.edu/paulevans/viticulture1.html
Member: CBHL, USAIN, ALA, ACRL, IAALD