[NAFEX] Apple - Alkaline Water - Powdery Mildew
Docshiva at Docshiva.org
Fri Jun 10 19:04:57 EDT 2005
A lot of lore about powdery mildew indicates that unlike other fungi, it
appreciates a somewhat acidic, dry, and cool environment. Your alkaline
water shoulda killed it. Do you just see curling or do you see the mildew?
In untreated sensitive cultivars the mildew usually exists on the plant,
invisible to the naked eye. It's benign until it 'blooms' - has a spurt of
growth and spore production. The keys to getting a fungus to bloom are
pretty mysterious. Other organisms and minerals are probably involved. I
remember a patch of lawn that was barren of fungi until someone parked an
old pickup truck on it. Rusty rain dripped from the front bumper, and a
line of Chanterelles popped up. There wasn't enough change in moisture and
shade, I wouldn't think, to have caused the bloom; more likely iron or
chromium acting as a biological catalyst. So maybe something else in your
splashes of water triggered the mildew into action. Calcium is not shown to
be favorable to powdery mildew.
Another possibility is that the environment on your apple leaves was acidic,
due to some bacteria or a low pH treatment, and the CaOH made raised the pH
to something more inviting to the pm.
Powdery mildew treatments aim to change the narrow pH range researchers
suppose it likes. Treatments push pH down (sulfur, vinegar);
up(hydroxides), or toward the middle (bicarbonates). A classic organic
spray is a 10% milk spray, calcium and all. There are also many recipes
that use baking soda and a wetting agent.
Stephen Sadler, Ph.D.
USDA 9, AHS heat zone 8,
Sacramento CA - Mediterranean climate
From: nafex-bounces at lists.ibiblio.org
[mailto:nafex-bounces at lists.ibiblio.org] On Behalf Of Thomas Olenio
Sent: Friday, June 10, 2005 2:34 PM
To: North American Fruit Explorers
Subject: [NAFEX] Apple - Alakaline Water - Powdery Mildew
Is there any connection between very alkaline water (dissolved calcium)
and powdery mildew (PM) in PM sensitive apple culitvars?
I have an odd observation...
We are in the midst of a heat wave in SW Ontario. The village water is
very hard, loaded with calcium.
When I watered the lawn, for it was burning out, the hard water hit the
leaves of the apple tree. Now the leaves of the tree are showing classic
PM, curling lengthwise. This apple cultavar is sensitive to PM.
Would alkaline water accelerate PM? This may be my problem if the link
Any expert input?
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.323 / Virus Database: 267.6.6 - Release Date: 06/08/2005
nafex mailing list
nafex at lists.ibiblio.org
**YOU MUST BE SUBSCRIBED TO POST!**
All other messages are discarded.
To subscribe or unsubscribe, go to the bottom of this page (also can be used
to change other email options):
File attachments are NOT stripped by this list
TAKE STEPS TO PROTECT YOURSELF FROM COMPUTER VIRUSES!
Please do not send binary files.
Use plain text ONLY in emails!
Message archives are here:
NAFEX web site: http://www.nafex.org/
More information about the nafex