Re: Borer control
- Subject: Re: Borer control
- From: B* S*
- Date: Mon, 02 Nov 1998 09:11:53 -0400
From: Bill Shear <BILLS@hsc.edu>
It is true that nematodes applied one year do not winter over to the next.
This is one of the main research areas in the field of nematology (in fact
my lab technician is going back to graduate school at UNC and will be
working on just this problem--why don't the nematodes establish populations
and provide continuing control?). The difficulty may lie in predators in
the soil that eat the nematodes, or in a lack of suitable hosts once the
nematodes have killed everything available.
Yes, nematodes are expensive, probably several times more costly in money
than insecticides. However, one avoids the 'hidden costs' of health
hazards and environmental damage in using insecticides. The chemmies never
include these 'hidden costs' in their analyses, and on a nationwide basis
they are substantial.
What are needed are more extensive field trials like those done in Maryland
several years ago, with attention paid to fall and spring cleanup as well.
I would suspect that with perhaps two years of nematode treatments, coupled
with clean-up, one could go to applying nematodes only once every few
years. Iris borer moths are not very mobile and so once the problem is
cleaned up, the chances of re-invasion are not great unless you are in the
middle of a lot of iris growers who don't pay the same attention to control.
Borers are the main problem in growing irises in the northeast, but are not
all that difficult to control, using a variety of methods (chemicals only
as a last resort) as outlined in my book. There is no reason to panic.
Steady, consistent work on controlling borers produces good results.
Nematodes are another weapon in our armimentarium, as yet not fully proven,
but very promising.
Bill Shear
Department of Biology
Hampden-Sydney College
Hampden-Sydney VA 23943
(804)223-6172
FAX (804)223-6374
email<bills@hsc.edu>
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