Hello, David — Did you apply any postharvest treatments to the affected fruit? Do the spots appear at points of fruit contact in the boxes as the fruit come out of storage? If answers to these two questions are positive, then toxicity from postharvest treatment solutions due to slow drying at contact points might be involved. If answers to the first two questions are negative, then my final question is whether you applied calcium sprays in the field during late summer?
As you can tell, I don’t know the cause of the damage shown in your photos. However, I have received or been sent photos of similar problems from many growers and consultants over the past 5 to 8 years. As you indicted, I have frequently noted what appears to be damage originating from a lenticel but then spreading to kill epidermal cells around the affected lenticel. In those cases, I suspect (but cannot prove) that the damage resulted from uptake via the lenticels of some toxicant (calcium, captan, other pesticide, air pollutants?) that weakened but did not immediately kill the cells around the lenticel. However these weakened cells later died during storage, resulting in blackened lenticels. And I suspect that diffusion of the toxicant from the lenticel entry point slowly killed other epidermal cells around that lenticel. In some cases, the toxicant may have been applied in a postharvest treatment, but I suspect that most damage of this kind is initiated in the field. Your photos, especially the one showing damage on the calyx points of the fruit, suggests that sprayed product may have pooled at the low points of the fruit during a preharvest spray, thereby allowing for excessive uptake that contributed to subsequent cell death during storage. In some cases, I have wondered if fruit that are too close to a sprayer nozzle during late season sprays may end up with lenticels that are damaged by direct exposure to the high-pressure output from passing nozzles, but I doubt that was the case for your fruit where single lesions seem to predominate. I wish we knew what the offending toxicants and/or contributing factors really are. Or, if anyone has a better explanation for the damage in the photos, I would love to hear it. ******************************************** Dave Rosenberger, Plant Pathologist, Hudson Valley Lab, P.O. Box 727, Highland, NY 12528 ******************************************** > On Nov 28, 2015, at 2:16 PM, David Kollas <kol...@frontier.com> wrote: > > > > The two photos here show a skin-deep discoloration now appearing in several > varieties of our stored fruit > (32-36F, air). In most cases I can distinguish a circular lighter-colored > zone centered on a lenticel, but this often merges into similar tan-colored > skin beyond the single lenticel. None of the spots I have seen is larger > than the > the diameter of a 5-cent coin. Affected skin is not different than normal > skin to the touch. There is no pitting or > depression in the affected area. Note that in one of the Mutsu fruits shown, > discoloration is limited to the calyx-end points. > > In several years I have seen scald symptoms near the end of storage season > (late February, March), but > now in mid-November, I don't expect to see superficial scald. I am wondering > whether others have seen > similar symptoms. > > > David Kollas > Kollas Orchard > Tolland, Connecticut; USA > > > <IMG_1260.jpeg><IMG_1262.jpeg>_______________________________________________ > apple-crop mailing list > apple-crop@virtualorchard.net > http://virtualorchard.net/mailman/listinfo/apple-crop _______________________________________________ apple-crop mailing list apple-crop@virtualorchard.net http://virtualorchard.net/mailman/listinfo/apple-crop
