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
>>> 
>>> 
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