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  - Serious spreading Amorph disease-Collar rot
From: rajshekhar misra rajshekharmisra at yahoo.com> on 2006.07.09 at 23:37:36(14403)
Dear Adams,
The symptoms described by you are typical symptoms of
Collar rot disease of Amorphophallus caused by
Sclerotium rolfsii. We frequently observe this disease
in India. The Fungus is seed borne and also soil
borne. You might have seen white fungal mycelial
growth and mustard like structures called Sclerotia on
the infected surface. You can use systemic fungicides
like Carbendazim (0.1%) as soil drench to prevent the
From: Adam Black epiphyte1 at earthlink.net> on 2006.07.16 at 23:23:15(14431)
Hi everybody,

I am a little late in thanking eveyone for their input on our diseased
Amorphophallus. Seemed like the consensus was either an Erwinia
bacterial infection or Sclerotium (Collar Rot) fungal infection, the
latter suggested by Dr. Misra and detailed in his excellent article in
Aroideana vol 26. The symptoms on our plants seem to match the
Sclerotium more closely.

To those of you that requested photos of the infected plants, I had
planned to do so, but after my original posting to the list on this
subject, I went back to work and could not find a single plant
infected, and still have yet to see any more diseased plants. I am
hopeful it has run its course. The symptoms appeared as we began
receiving more regular rains after being in drought conditions for
months here in north Florida, which correspond to Dr. Misra's
description of changing environmental factors causing these outbreaks.

Though we weren't keeping track of numbers of casualties, our A.
konjacs were hit the hardest, followed by A. bulbifer, but none of our
A. paeoniifolius showed any symptoms. I had mentioned that most of our
A. paeoniifolius were showing early signs of the disease, but upon
closer examination, I figured out that the lawn service that maintains
the grassy areas of the gardens had gone through with a weed-eater and
trimmed the grass growing at the base of the petioles, whipping gashes
in the base of the petioles. These injuries don't seem to be getting
infected, and hopefully since the supposed Sclerotium outbreak has
settled down, we won't see any more, for now at least. I still plan do
do a soil drench with a systemic fungicide as Dr. Misra recommended
just in case. And I have explained to the lawn service to keep their
weed eaters away from the "giant celery lookin' things" as they called

Thanks again for everyone's help in this matter.


From: bonaventure at optonline.net on 2006.07.22 at 18:59:40(14436)
Do you mean you grow your paeoniifolius in the ground outdoors? What hardiness zone are you? I pot mine and bring them inside in late October before our first expected frost, along with mossambicensis, and immature lewelii and henryii, and Taccarum wendelianum, and now also Amorph. bulbifer, which I almost lost completely. They then are not watered until May, and the petioles undergo a long and gruesome collapse and drying off before they can be plucked off. Only my konjacs, yunnanensis, dunnii, and of course Typhonium venosum winter over outdoors and are permanently planted in the soil.
Bonaventure Magrys
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