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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