North American Fruit Explorers mailing list at ibiblio

[nottke <nottke1@earthlink.net>]

A few months ago, there were a few postings about black spots appearing at
the water drip-off point on several varieties of plums, including all of my
varieties, which are Asian in origin.  It is the first time I have seen
such spots in several years of harvesting from these trees.  I do not
recollect anyone on the listserve having a good explanation for it.

During the growing season I culled out as many of the spot-bearing plums as
I could as I thinned the crop, but about half of the final remaining fruits
had the spot.

Now that I have finished harvesting the crop, I conclude the the spots were
a non-serious blemish.  The spots (never more than one per fruit) grew
slower than the rest of the skin, but splits in some of the fruits due to
our very wet Spring did not often initiate at the black spot.  Also the
black spot was not a common source of rot or insect damage.  In processing,
the black spot seemed to be a thin, flexible area of skin with no
discernable off-flavor, and it faded to maroon in hot-processed fruit
(cooked jam).

Comments?

Jim Nottke
Pfafftown, NC 27040
Hardiness Zone 7A