"Whoops there goes another apple tree plant.." Two more, actually, victims of
Saperda candida. The one I knew about, as the borer holes were visible and I had
been attempting control. The other was a few cm. below the soil surface, though,
and not visible. (Both trees blew over, broken at the weakened trunk, in the storm
last week).
My understanding is that this is a relatively new problem, although around the early
1900's in New York it was suggested that Saperda could wipe out the entire apple
industry. It then became nothing more than a minor pest, with the introduction of
regular sprays for other pests. Now, with the growth of organic agriculture it is
making a come-back. My own trees are largely "organic", (although it is more by
neglect than philosophy), and I am having ongoing problems with Saperda. I have
painted the trunks with a mix of latex paint and lime. Where I can detect the frass
from Saperda activity I have been injecting insecticide directly into the holes. (But I
have not been able find out what insecticide is the best one to use. Older
references specify endosulfan, but this has been removed from the market in both
Canada and the States.) (This process of injecting insecticide directly into the holes
is my own invention - I am a physician, and have ready access to syringes and
needles.) The advice to poke a wire into the holes is a complete waste of time - the
holes are frequently crooked, and the wire doesn't get up (or down) to where the
grub is. Has anybody got any more ideas or experience in managing this pest?
The attacks below the soil surface are a particular problem, as I can't go around
uncovering the roots of 181 trees (used to be 183...) every few months, looking for
signs of attack.
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