RE: [compost_tea] Re: Phytopathology journal article on compost tea, November 2004
Hi Ted, Tom, Titel, and others.
It’s been a while since I posted las=
t, but I do still read the posts and I thought that I could shed some light=
on this subject of powdery mildew and compost tea. First off, you gu=
ys are talking about different pathogens. Grape powdery mildew caused=
by Uncinula necator, which is different from the powdery mildew on roses w=
hich is caused by Sphaerotheca pannosa. Thus you can't really compare=
the effects from tea on the powdery mildew on these different plants becau=
se were talking about different pathogens. Second, since powdery mild=
ew usually prefers dry weather and does not like rain, it is possible that =
spraying just plain water will result in a reduction of infection. &nb=
sp;
In our research at Rodale we found that ACT =
did suppress grape powdery mildew at one of the vineyards in one of the two=
years were experimented, but this was only about 50% suppression and was n=
ot adequate from the grower’s perspective. In the second year=
we did not observe any powdery mildew suppression at any of the three vine=
yards we were collaborating with. So it seems like there is potential=
, but ACT for disease suppression really needs some major developments befo=
re it can be recommended with confidence (ie. purchase crop if suppression =
fails like Ted mentioned) to growers.
I also wanted to mention that Tom has a good=
point - "As hard as I search I still haven’t found an article=
on disease suppression supporting ACT by your methodologies".
I hope that I have not offended anybody, jus=
t wanted to shed some light in a constructive sense.
Matt Ryan
The Rodale Institute
-----Original Message-----
From: Ted Peterson [mailto:ted.peterson_at_tcsn=
.net]
Sent: Thu 10/21/2004 2:19 AM
To: compost_tea_at_yahoogroups.com
Cc:
Subject: Re: [compost_tea] Re: Phytopatholog=
y journal article on compost tea, November 2004
----- Original Message -----
From: Titel Ryzhomer <mailto:thegoodjob_at_h=
otmail.com>
To: compost_tea_at_yahoogroups.com
Sent: Wednesday, October 20, 2004 4:15 PM
=
Subject: [compost_tea] Re: Phytopathology jo=
urnal article on compost tea, November 2004
Hi Ted,
Yes, I've actually observed with magnificati=
on the powdery mildew
structure breaking down after spraying (unde=
r magnification it has a
building block, almost geodesic (sp) structu=
re) and eventually
disappearing, sometimes leaving a scar. This=
efficacy has not been
apparent with every batch of CT, however oth=
er batches have helped
to control it as you have indicated regardin=
g grape plants. I am
aware that there are many types of powdery m=
ildew and perhaps this
CT is working only on the variety we have gr=
owing here on
delphineas, roses, some herbs, Indian Hemp o=
r Dogbane {Apocynum
androsaemifolium} and a weed that appears to=
belong to the Evening
Primrose family. It has been quite easy to i=
nduce the powdery mildew
(for research purposes) through use of poor =
growing conditions, etc.
I hope this helps to clarify.
Regards,
Titel
Well, I will have to say this is amazing.&nb=
sp; In all the tests I have run here I have seen nothing like this. W=
e have several vinyards using different brewers from different makers and s=
ome home ones knocked off of mine and Earth Works and a lot of different re=
cipes. I haven't heard reports like yours from any of them. Mos=
t vinyards use Roses as indicator plants because powdery mildew will usuall=
y show up there before grapes. If the vinyard people see it on the roses th=
ey can be pretty sure it's in the vines. I tried spraying right on th=
e roses with full strength tea and it did nothing to the mildew that was al=
ready there. It did prevent the mildew from spreading but did absolut=
ely nothing to the existing mildew on the plant. In addition, I had t=
o spray every day to prevent the spread. When I stopped spraying, the=
mildew started spreading in 1 to 2 weeks depending on mildew pressure.
=
Do you have controls? Did you try spra=
ying with just molasses or just water? Could it be that there was a r=
esidue of fungicide that was activated when you sprayed? Was the spra=
yer you used completely clean of fungicides? Did you add anything to =
the tea that was a form of organic fungicide that you didn't explain in you=
r message?
Here is the problem I have: I did not =
see and have not seen anything even close to what you are describing. =
If I believe what you say and go to a vinyard and present CT as able to cu=
re powdery mildew and it doesn't, I am financially responsible for their lo=
ss of product. Are you sure enough of what you posted about eradicati=
on of powdery mildew to back up that claim to a grower? Would you be =
willing to go to a grower and state if he follows your directions and the m=
ildew does not subside that you would compensate him for the loss?
The tests I made were on conventional vines,=
organic vines and patches that were separated by enough distance to give p=
retty accuract results. One vinyard was in a medium to high mildew pr=
essure area and the other was in an area that was traditionally low mildew =
pressure. I did see the outbreaks controlled in every vinyard I have =
applied tea instead of conventional fungicide but even in the most successf=
ul vinyards, we got minor outbreaks. I treated those with fungicide a=
fter I determined that tea could do nothing to eradicate the mildew. =
So your post is very interesting to me. Do you have any lab test to s=
ubstantiate what you say? Would you be willing to let me contact the =
grower and find out his/her impression of what happened? If what you =
say is true, you may have found something worth a fortune to organic grower=
s.
I now have contracts with 5 vinyards and hav=
e sprayed a lot of tea over almost three years. I have done a lot of =
tests and am still unprepared to make the statement you have made after 7 m=
onths so I am very interested to learn where you are having success when no=
body I know, even other consultants, are having the same results.
You mentioned inducing mildew as the result =
of poor growing conditions. The spread of mildew has not been the res=
ult of poor growing conditions as far as I can tell. It attacks both =
conventional and organicically managed plants with equal vengence. I =
have seen it attack in extremely well managed vinyards and skip poorly mana=
ged vinyards and vice-versa.
Ted Peterson
EW/SOE
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Received on Mon Oct 25 2004 - 17:48:32 EDT
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