Re: dying hosta
I believe Southern Blight and Crown Rot are 2 different pathogens. The
symptoms I have observed of SB, are the leaves fall over beginning at
the perimeter of the plant and work inward, until all have fallen over
and are lying flat on the ground. Removing a leaf it looks rotted at
the base and is mushy. There appears to be a white powdery substance at
the base and the mustard seed spores are evident.
Crown Rot the leaves brown beginning at the edges and move rapidly down
the leaf toward the petiole. The leaves may still remain upright, but
if you pull them off they pull away easily and are also mushy and have
an odor. Incidently the symptoms I have experienced of heat dormancy
are similar, but the leaves don't pull away easliy and there is no odor.
At the AHS convention I asked Bob Solberg what to use for SB. He
suggested the bleach solution and as an alternative, terrachlor, a
fungicide.
At the Midwest Copnvention in July, I got in a discussion with Mark
Zilis and Gerry Hadrava about CR. Gerry said he uses a combination of
fungicides. He mixes them together to create a broad spectrum product.
In other words if one doesn't work, the others will. Bleach was also
suggested, but the fungicide was prefered. Sorry but I can't remember
the fungicieds Gerry uses. They were common named fungicides that are
readily available.
I had a mature plant of Collosal, 2 feet high and 5 feet wide, 3 years
ago that exibited signs of crown rot. I tried powdered sulphur, then
bleach when it appeared the sulphur wasn't working. Finally the plant
withered to nothing. It was gone in one season. I removed the rotted
crowns, and drenched the soil with more bleach and a fungicide. I
didn't replant until this year. It has spread into other plants in the
area. I have treated with a fungicide every 2 weeks all season. It
seems to have halted the spread.
I had SB on a Mountain Snow several years ago. It did not kill the
plant like the CR did. The SB only stunted it and made it look bad the
rest of the season.
Needless to say I have more respect for these diseases. If I suspect
anything, I get out the arsinal. Incidentally the fungicides and bleach
are poured directly ovetr the crown of the plant and surrounding soil.
A thourough drenching.
--
Tom Micheletti
The Hosta Patch
Deer Park, IL
www.hostapatch.com
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