North American Fruit Explorers mailing list at ibiblio

[Alan Haigh <alandhaigh@gmail.com>]

I never had a problem with borers in plums in over 20 years of growing
hundreds of trees in southeastern NY but last year they struck with a
vengeance for the first time.  Funny how all those years they were going
after nearby peach trees but left the plums alone.  Because I mulch my
nursery trees (yes, right up to the trunk, against most guidelines), which
were the ones badly hit, I didn't notice them until a lot of damage was
already done.  Fortunately I'm licensed for high risk pesticides so I was
able to spray the trees with Lorsban.  I wouldn't want to count on fishing
the suckers out with a wire although I've done lots of that in peach trees
over the years.

The usual proscribed home method cure is to dig down to first roots and
spread some moth balls by the base and then covering with soil.  I believe
you can also foil the egg laying by wrapping the base of the trees (going
down to first roots below graft) with nylon screen held with rubber electric
tape.

As for my plum trees, all but one survived but some are growing with reduced
vigor which I can only hope turns around next season.  There's a lot of
callous on the root crown.  The Euro plums have suffered much more than the
J. plums which I assume is due to greater vigor of the latter.  High vigor
is a very good defense against this pest and peach trees in this state are
seldom killed by borers in my exp.