Thank you !
----- Original Message -----
From: Arthur Harvey
To: Apple-Crop
Sent: Thursday, February 11, 2010 4:34 PM
Subject: Re: Apple-Crop: treatments vs genetic traits
From my limited experience it appears that finding varieties with
resistant traits is a more promising way to pursue compared with treatments.
It is well known that certain strains of Baldwin are relatively immune to
scab---why cannot this genetic trait be worked into other varieties. Also, we
have a local seedling here in western Maine which not only resists freezing
until the first week of November---and keeps well---but also sheds
insect-damaged apples so that only perfect ones mature. Seems like
characteristics that would be useful elsewhere.
On another topic, the federal law governing organic foods was amended
by lobbyists hired by some manufacturers, working with the so-called "Organic
Trade Association". This will allow synthetic ingredients to be added to
organic-labeled foods.
If this is important to you, please visit my website,
www.RestoreOrganicLaw.org
--- On Thu, 2/11/10, Dave Rosenberger <da...@cornell.edu> wrote:
From: Dave Rosenberger <da...@cornell.edu>
Subject: Re: Apple-Crop: Attaching trees to trellis
To: apple-crop@virtualorchard.net
Date: Thursday, February 11, 2010, 4:41 PM
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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