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nafex - Re: [NAFEX] Powdery mildew on Constort black currants

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  • From: Richard Moyer <ramoyer@gmail.com>
  • To: nafex@lists.ibiblio.org
  • Subject: Re: [NAFEX] Powdery mildew on Constort black currants
  • Date: Sun, 26 Jun 2011 21:48:23 -0400

Meikal,
Was looking into this recently for powdery mildew on peas:
---Researchers in Brazil have studied various concentrations of milk,
and various milk products for mildew control. If I remember
correctly, full-fat, skim or whey soln works equally well. Powdered
milk or whey can be used, for room temp storage of concentrated
product. Search 'Bettiol, Brazil, milk and mildew' to read some of
the research results. New Zealand work also.
---Perhaps our list resident research librarian can do a search for us
and post some of the better comparative studies on milk control of
mildew? Please let us know if you are able.
---Various concentrations have been tried, and a wide range are
effective, though phytotoxicity shows up when milk is at 30%. 10-15%
has been reported as effective for mildew as higher concentrations.
---I presume part of the confusion is due to sharing of anectdotes.
Read some of the comparative research, at least to get a sense of what
worked, on what plants, in those studies. See this link as a start:
http://www.hartley-botanic.co.uk/gardening-tips/matthew-biggs/removing-powdery-mildew-on-gooseberries
---JMS Stylet Oil is very effective on powdery mildew (also called
American Gooseberry Mildew), and is purported to kill the spores to
keep it from coming back. My impression is that milk soln lacks the
spore killing ability, though I could be wrong.
---Dr. Kim Hummer, USDA-ARS currant and gooseberry researcher in
Corvallis, OR, has directed research on the use of stylet oil for
mildew control. Kim is very approachable, and would likely be glad to
answer your questions on mildew control on Consort. She also is
committed to maintaining the Ribes collection with the absolute
minimum of chemical treatments, so to better advise in situations such
as yours.
---If you contact her, she may ask graciously about even growing
Consort, with its known mildew susceptibility and general perception
of inferior (outright bad) flavor. Kim and her researchers have
screened a number of black currants that are resistant to both mildew
and rust, and taste so much better than Consort.
---Some Dutch growers of red currants cut 1/2 of their planting to the
ground each year. I presume after harvest, though check if you use
this route. Stylet oil can then be used to effectively rid the plant
crowns of mildew spores, then the regrowth may have enough time to
bear next year.
---But if you're going that route of cutting all (or a portion) of the
plants to the ground to control the mildew, now may be the ideal time
to bring in some better black currant genetics, for resistance to
mildew and rust, and for better flavor. Remember you can request
limited amounts of material from the NCGR Repositories, so you could
compare the mildew resistance of some other cultivars to your Consort.
Black currant cuttings root easily.
---At the NAFEX meeting in NH, one of the orchards we visited had a
long row of Consort, Coronet or Crusader, and the grower noted than it
was the one fruit he couldn't get his U-pick customers to buy. We
suggested he look into some of the better flavored cultivars.

So in summary, you can manage mildew on new growth with milk in
various forms, 10-20% solution, but the mildew spores may still be
viable, waiting until your milk soln washes off. Look into Stylet oil
as a more effective organic control. Again, Kim is quite interested
in encouraging currant growers. She'd be more than happy to help.
Just know she may suggest other cultivars as a long term solution.

Richard Moyer
SW VA
Nibbled today on wintergreen (tea) berries while hiking at 4000'.
Previous year berries still in good shape, while blooming for new
crop. Any other temperate fruits that manage this?


Date: Sun, 26 Jun 2011 08:37:54 -0500
From: mIEKAL aND <qazingulaza@gmail.com>
Subject: [NAFEX] Powdery mildew on Consort black currants
To: North American Fruit Explorers <nafex@lists.ibiblio.org>
Message-ID: <BANLkTikAtpPx+_b1yEqr+5rkB_nvUDZw=A@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

We've had about 3 weeks of rain & the powdery mildew has bloomed
profusely on a row of a 100 Consort black currants. Searching around,
it seems the number one organic control is spraying a dilute solution
of milk (which I'd like to try since I work for an organic milk
company..) I see a number of recipes, 1 milk to 10 water. Another
recipe says half & half. Some say use whole milk, some say use skim.
Does anyone have experience with this?

I'm also seeing in a number of other place to cut back the plants
below the investation & burn everything, which seems drastic. Seems to
be multiple conflicting schools of thought about this.

~mIEKAL




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