North American Fruit Explorers mailing list at ibiblio

[Alan Haigh <alandhaigh@gmail.com>]

Sherwin, I don't think you disagree, just misunderstand my meaning.
Italian plum is not  the same as Stanley and has more resistance to black
knot based on my own observation.  Stanley is sometimes defined as an
Italian type plum, but Italian also refers to a specific variety also known
as Fellenberg.  Stanley is not worth growing, in my opinion, in spite of
its consistent cropping, because it drops fruit off the tree before it is
truly ripe.  A prune plum is unfit for eating until the flesh is a rich
amber, as far as my palate is concerned.  Why settle for a 12 brix when you
can get over 20?

Black knot comes in cycles probably determined by the timing of rain and
level of humidity.  It is also worse on sites with poor eastern exposure
and obviously with infected native cherries nearby.  Keeping trees open
with summer pruning can also be helpful as is cutting out the black knot
repeatedly during the growing season when it is spreading badly.

As plums go, Methely is the absolute worst sponge for this disease that I
grow, and can increase problems for all nearby plums, much like quince with
fireblight.

I manage many varieties of plums on many different sites and have been
afforded the opportunity of lots of anecdotal comparison of  plums over the
years.  It is still only anecdotal, of course.