Hello, Ricardo --
First, it would be helpful to know in what geographic area
and/or climatic region you wish to grow organic fruit. Options vary
based on location, with disease control being MUCH simpler in arid
production areas than in warm and humid production areas.
I'm not certain that any pathologists have focused efforts on
DISCOVERY of new products for organic tree fruit production. Since
the 1950's, pesticide discovery has been mostly left to commercial
enterprises because university scientists are poorly equipped to
register and commercialize new products. Over the past 20 years, I
am aware of perhaps a half dozen pathologists who have attempted to
commercialize biocontrols, and most of these efforts have either
gotten bogged down prior to commercialization or the final products
were of such limited usefulness that they soon disappeared.
However, I and several other pathologists at land grant
institutions in the northeastern US have been EVALUATING new products
for organic production over the past 15 years. Generally, we have
looked at any promising candidates that gained EPA registrations,
although I'm certain that there are some things that no one has yet
evaluated because the manufacturers have been unable to provide even
a shred of evidence or logic as to why their products should work.
Some of these university evaluations have been done in certified
organic orchards and some have been done via replicated plot studies
within larger trials that included other non-organic pesticides.
I think we all know that sulfur, copper, and lime-sulfur are
effective against various diseases on tree fruit, and OMRI-approved
formulations of these old stand-bys are available. Some other OMRI
approved products may have reasonable activity against powdery
mildews, but so does sulfur. Furthermore, mildews are usually only a
minor part of the total disease picture for most tree fruit crops.
Although there is a lot of advertising and hype about
biocontrols and new organically acceptable products that will control
fungal diseases, the simple fact is that we still have not identified
any organically-acceptable fungicides are consistently effective for
protecting apple leaves and fruit from fungal diseases (i.e., that
work better than copper, sulfur, or lime-sulfur). I'm less familiar
with recent research on stone fruits, but I believe that the same
statement would apply. I know that some products such as Serenade
are being used commercially, but most growers I speak to about these
products either have no evidence of effectiveness (i.e., no
controlled comparisons) or they admit that they include the
biofungicides just to mollify certifying agencies even though they
recognize that these products are relatively ineffective.
If other readers have opinions and evidence that contradicts
my perspectives, I'd certainly be interested in hearing about it.
Is anyone aware of plant pathologists who may be working on the
development of fungicides suitable for organic production of tree
fruits?
Thank you
Ricardo Menendez
--
**************************************************************
Dave Rosenberger
Professor of Plant Pathology Office: 845-691-7231
Cornell University's Hudson Valley Lab Fax: 845-691-2719
P.O. Box 727, Highland, NY 12528 Cell: 845-594-3060
http://www.nysaes.cornell.edu/pp/faculty/rosenberger/
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