Skip to Content.
Sympa Menu

compostteas - [Compostteas] Re: Re: powdery mildew (laura_s@vaxxine.com)

compostteas AT lists.ibiblio.org

Subject: Compost Teas: 24 hour, EM, IM, BD & fermented plant extracts

List archive

Chronological Thread  
  • From: "Soil Foodweb, Inc." <info AT soilfoodweb.com>
  • To: compostteas AT lists.ibiblio.org
  • Subject: [Compostteas] Re: Re: powdery mildew (laura_s AT vaxxine.com)
  • Date: Fri, 12 Jul 2002 09:03:10 -0500

Hi Laura -

This happened to us last year in the SARE grant, when we were testing dose
response. That means, we were doing treatments that were: 12 gallons per
acre of an ok
tea (we were getting only half the fungi we wanted), 8 gallons per acre of
the tea, and 6 gallons per acre of the tea.

In the 6 gallons per acre treatment, about two months after the conventional
people began having problem, the plot that was treated every 2 weeks came
down with
serious mildew problems. And I mean, bad mildew problem. The mildew moved
into the treatment that was getting tea once a week as well.

At this point, chemicals were necessary. On your vines, if the mildew can't
be controlled with an immediate tea drench of the vines, apply potassium
bicarbonate
to suck the moisture out of the mildew.

Several companies sell this, Armicarb, for example from Helena Chemical Co,
but several other compnaies sell their version of this, so ask your local
Wilbur-Ellis
folks or Farm Services folks for their version - I don't know if one
company's version is better than others. Again, testing is needed.

But they all work on the same principle - osmotic shock. I'm not sure the
concentration needed, but something like 3% potassium bicarbonate in water
should
work. Although, directions on the container of the bicarbonate you buy would
be more reliable than my memory.

Apply the potassium bicarbonate (carbonate probably would work too, as well
as sodium bicarbonate except that is sodium you are applying to your vineyard
then),
and wait three days to let the chemical do it's job of drying up the mildew.

I would apply the chemical out a good 100 feet from the area of infestation
with mildew just to make sure you got the problem area. If it's too
difficult to
limit the application to a limited area, do the whole vineyard.

Three days after the chemical application, do another tea and resume the tea
applications. Scout the vineyard to make sure no other areas succumb to the
disease.

There are two likely reasons for the outbreak. First, inadequate fungal
competitors got onto the leaves from the teas. Most likely the teas you have
been
applying weren't fungal enough. Secondly, there may have been residues of
chemicals (sulfur allowed by organic programs is a pesticide) in the vineyard
and they
had to be dealt with by the biology you are applying before the biology can
get established on the leaves. Checking your leaves right after a spray is a
good way
to establish that the organisms are surviving on the leaves.

We're doing the same three vineyards with the SARE grant this summer, and all
three are doing just fine. No mildew problems in these areas of these
vineyards
even though the Willamette Valley is having a serious mildew year. Not as
bad as last year, understand, but serious. Because all treatments are at the
high
fungal dose, no outbreaks this year. So far.

So, next year you will have an easier time of controlling the mildew, because
you will start the tea two weeks before bud-break and have the protective
biology on
the vines BEFORE the mildew spores arrive.

Please keep me posted on how it goes. We need to have a central clearing
house of how these things work, and SFI is glad to be that central
information center.

Elaine Ingham
Soil Foodweb Inc.

> Subject: [Compostteas] Re: powdery mildew
>
> I have sprayed my vineyard with CT since the beginning of the season. A few
> days ago we noticed some powdery mildew. Not alot but some.
>
> Any suggestions as to whether the tea should be more fungal or bacterial to
> protect the vines against pwodery ?
>
> Should there be a waiting period, and if so how long, prior to applying CT
> after using sulphur or Bordeau ?
>
> Laura Sabourin
> Feast of Fields Inc
> Demeter Certified Vineyard & Farm http://www.ragdolls.net/vineyard.htm
> Ragenesque Ragdoll Cattery http://www.ragdolls.net/ragenesq.htm
> R R # 1
> St Catharines, Ontario L2R 6P7
>




  • [Compostteas] Re: Re: powdery mildew (laura_s AT vaxxine.com), Soil Foodweb, Inc., 07/12/2002

Archive powered by MHonArc 2.6.24.

Top of Page