Thanks for the follow-up explanation, David. Like you, I am surprised that dried residue from a detergent would be so toxic to apple skins.
> On Nov 29, 2015, at 11:04 PM, David Kollas <kol...@frontier.com> wrote: > > Today I have some additional observations concerning the skin disorder. > > The fruits in the photos of my previous posting were collected by my > wife, Janet, during her sorting of > fruit for the farm salesroom. Yesterday I asked her to notice, during > sorting, whether spotted fruits were randomly distributed in the crates; or > instead perhaps, only found in contact with the walls or bottom of the > crates. In today’s sorting, she found the spots only on fruits bearing > against a wall or bottom. Only about 25 percent of such fruits showed the > spots. > The crates we use are standard 6 gallon plastic milk crates made in > Connecticut. To prevent cutting of > fruit by the sharp-edged interior walls of these crates, we installed > polypropylene mesh on all interior surfaces. > We have used these tamed crates for harvest,storage, sorting,and sales > display for the past 15 years. No post-harvest dips or flooding is applied. > No calcium sprays have been used pre harvest or post harvest. Every year, > some or most of the crates are cleaned and sanitized to remove dust and > visible fungus.The cleaning/sanitizing is done by dipping crates in an > aqueous mix of household bleach and dishwasher detergent. Janet and I sort > of split the responsibilities here; we call her the Vice President for > Marketing, so crate cleaning fell to her. She asked me about skipping the > rinse step last summer. I said, Sure, the chlorine evaporates and > disappears. I, ahh...did not consider possible burn to fruit from the > detergent. I think now the rinse step will be reinstated. > I would rather have found some explanation that would leave me > guiltless, but I do feel better in the confidence that this injury will not > likely appear here in future years. > > Dave R.: I appreciate your efforts and willingness to elaborate as you > do. This particular skin disorder may never present itself to you again, but > if it does, you will think of this unusual explanation to add to your list of > possibilities. > > David Kollas > Kollas Orchard > > On Nov 29, 2015, at 7:48 PM, David A. Rosenberger <da...@cornell.edu> wrote: > >> 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 >>> firstname.lastname@example.org >>> http://virtualorchard.net/mailman/listinfo/apple-crop >> >> _______________________________________________ >> apple-crop mailing list >> email@example.com >> http://virtualorchard.net/mailman/listinfo/apple-crop > > _______________________________________________ > apple-crop mailing list > firstname.lastname@example.org > http://virtualorchard.net/mailman/listinfo/apple-crop _______________________________________________ apple-crop mailing list email@example.com http://virtualorchard.net/mailman/listinfo/apple-crop