>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 <[email protected]> wrote: From: Dave Rosenberger <[email protected]> Subject: Re: Apple-Crop: Attaching trees to trellis To: [email protected] 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/ -------------------------------------------------------------------------- The 'Apple-Crop' LISTSERV is sponsored by the Virtual Orchard <http://www.virtualorchard.net> and managed by Win Cowgill and Jon Clements <[email protected]>. Apple-Crop is not moderated. Therefore, the statements do not represent "official" opinions and the Virtual Orchard takes no responsibility for the content.
