Re: Phytophthora Root Rot

Hi, I don't know about phytophora and pumpkins, be we have a major problem in
W.A with Phytophora cinnamomi and our Jarrah forest. We call it dieback as it
prevents the roots from taking up water, and thus the leaves and branches at
the top of the tree die first, slowly (or rapidly) killing the rest of the
tree.
Huge amounts of money are being spent on it now, but so far not much has
happened.
You could try sterilising the soil (if the volumne isn't too large), and
improving drainage. The disease, like moist conditions, and if drainage and
slope are able to be changed, it can help. The didease spreads very slowly
uphill, and tends to follow water paths through the soil.
"The principle means by which P. cinnamomi infects plants is through the
production and dissemination of motile zoospores which swim  through water in
the soil to reach new potential hosts. At the root surface the zoospores
encyst, germinate and invade the root tissue."
The use of Phosphonate  as a fungicide is being tried, both as direct injection
and ground application, and also broad scale aerial spraying. Apparently it is
a derivative of Phosphonic acid used in confectionary manufacture, but I'm not
too clear on all the details.
The national parks board in Tasmania has some info online,  try
http://www.parks.tas.gov.au/phytop/index.html
 If you want any more info, I can look it up in some books etc I have, but I
really don't know much about management other than prevention. - ie try and
avoid soil disturbace and transportation. I know it can lay dormant for a long
time (years) in dry soil, and then when the conditions are right attacks etc.
Sorry if this is a bit jumbled and unclear, but I haven't looked at it for a
coupke of years and am a bit unclear. The quote above re: transportation is
from an essay I wrote in first year.
Hope this helps, if you need more info email me.

Audrey Hutton wrote:

> Greatly appreciate any information or experiences with Phytophthora Root
> Rot fungus.  I haven't been able produce any AG in my garden for the past 3
> years due to this disease.  Also, have had major problems producing decent
> broccoli, cauliflower, and a number of other crops due to a type of rot for
> about 6 years.  I suspect this is related to the same fungal disease I have
> in my pumpkins.
>
> I sent a sample of the main root, vine, and leaves from an AG to the U of I
> plant clinic, and they determined that Phythphthora Fungus was present.
> Evidently fungicides have no effect on this disease, and I'll probably have
> to plant in a new location, at least for a number of years.
>
> Have plenty of good seeds, but they don't do me any good if I can't set any
> fruit and my vines die a slow painful death.   Help!!
>
> Charles Tribout
> Decatur, IL



--
John McKinney
http://www.wantree.com.au/~oliverm/
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