Re: nematodes and borers
- Subject: Re: [sibrob] nematodes and borers
- From: J*@aol.com
- Date: Sun, 15 Jul 2001 21:34:16 EDT
We have used beneficial nematodes twice for iris borer with little success.
Technically it should work if you spray at the right time, but that is a
Catch 22 here in the Northeast.
Beneficial nematodes can only survive in soil temperatures above 45 degrees.
They are not really active until the soil temperature gets above 60-70
degrees. So if you spread them in the spring when the borer eggs are
hatching they are not likely to be active enough to parasitize them (if they
survive at all). If you spread them later in the spring when the soil has
warmed up, the borer's are already up inside the leaves and not likely to be
attacked by the nematodes. And to make it more complicated, you can only
spread them when the soil is really moist and this spring, even though we had
some very warm days, we also had a drought and had to wait for it to end
before spreading the nematodes.
On the more positive side, we have had very good luck with using nematodes
against cutworms, which are a very serious problem here for irises and
everything else. Since the cutworms are in the soil rather than inside the
leaves the nematodes can get to them easily.
I do not think that spreading nematodes now would do any good against borer.
Spraying with nasty chemicals wouldn't work now either.
Jan Sacks in Carlisle MA Zone 5 where the weather has been magnificent for a
week. 70's in July! Wonderful.
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