Re: anti-borer tactics
Thanks, Clarence, for the negative on malathion, though I'm not sure this
fellow who asked will stop using it: he believes it solved the problem of
stunted and deformed leaves he originally sought help with. Something
apparently did, but who knows what was going on. Don't know who gave him the
advice, either. I just hate to see anybody releasing that stuff into their
local atmosphere without a good reason and without knowing more about how much
or little or when they should be spraying.
Another possible anti-borer ploy occurred to me while weeding yesterday: How
about a 'decoy' spot in the garden, where one or two spare irises (ones you can
stand to sacrifice) are growing; you leave the dead iris foliage on that spot,
while keeping the real iris bed(s) scrupulously clean. The theory is that the
borer moth would be attracted to the decoy, and in late winter/early spring the
whole Borer Motel would be gathered up and disposed of, irises and all (a
variant on Clarence's late-winter cleanup approach). Has anyone tried this or
heard of it?
Linda's question about the adult's possibly specialized food requirements
points to another strategy: If the host plant did turn out to be something very
particular, maybe something could be applied to it that would kill the moth.
Might be hard to ensure you're not putting the hurt on some other insect that
relies on the same plant, but worth looking into....
Nell Lancaster, Lexington, VA email@example.com USDA zone 6b