Borers again

Last autumn I made a very special effort to clear up all debris around
my irises as I did not wish to use Cygon this year.  Everything was
spotless - almost polished!  This spring, I repeated the process in
order to get the few eggs that remained behind overwinter.  The result
has been that I cannot find any borer larvae on any irises, with three
exceptions.  On two plants, I found very young larve (3mm) that were
grazing on the leaf surface and taking off the epidermis.  This resulted
in weak leaves which were easily broken off.  also some holes and nicks
at the edges.  The two species were graminea and ensata and the plants
were next to each other.  The third species was bucharica.  The larve
just about eat off the whole of the emerging plant when it was about two
inches above the ground.  These plants, about five, have been eaten back
down to ground level.  Far more damaging than in other irises.

The result was that these three patches have been Cygoned to the point
that they nearly drowned.  I just hope that they survive the ordeal. 
The good news is that I sprayed three individual clumps, rather than the
whole garden.

Ian, in Ottawa
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