[permaculture] Silicon as fungal spray
steved at ncatark.uark.edu
Thu Mar 28 22:31:09 EST 2002
Silica/Silicate as a material to control diseases in greenhouse
crops can be found the ag journals. In Canada, I'm pretty sure
it has become a regular greenhouse industry practice to
use something like potassium silicate. It is good for pythium
and mildews on crops like greenhouse cucumbers.
Quarles, W. 1995. The truth about horsetails or natural plant
disease protection from Silica. Common Sense Pest Control
Quarterly. Vol. 11, No. 2 (Spring). p. 18.
Cherif, M. ; Benhamou, N. ; Menzies, J.G. ; Belanger, R.R.
1992. Silicon induced resistance in cucumber plants against
Pythium ultimum. Physiological and molecular plant pathology.
41, no. 6 (Dec 1992): p. 411-425.
Menzies,-J.; Bowen,-P.; Ehret,-D.; Glass,-A.D.M.
Foliar applications of potassium silicate reduce severity of powdery
mildew on cucumber, muskmelon, and zucchini squash.
J-Am-Soc-Hortic-Sci. Alexandria, Va. :. Nov 1992. v.
117 (6). p. 902-905..
Use of potassium silicate amendments in recirculating nutrient
solutions to suppress Pythium ultimum on long English cucumber.
Plant-Dis. St. Paul, Minn. : American Phytopathological Society.
Oct 1992. v. 76 (10) p. 1008-1011.
For mildew, a well established control is baking soda;
it apparently works even better mixed with horticultural oil.
Use of Baking Soda as a Fungicide
Mildews are one of the principle diseases that compost teas
are know to control well. Compost teas are becoming a regular
practice in vineyards, for example.
Notes on Compost Teas
Allan already mentioned BD 501, Horn Silica. The other
BD practice that is largely a silica effect, is horsetail tea.
Equisetum leaves are soaked in water and foliar applied,
largely as a prophylactic to prevent disease but also for
its total contribution of bioactive components that function
as a biostimulant.
I'd be comfortable recommending horsetail tea, baking soda,
or compost tea to a commercial nursery for the control of
many diseases. Of course, it ultimately is a trial and error
deal until the grower knows what works and confidence is
there to junk the fungicides and swith to a biological program.
For the green industry, biologicals are becoming more
available and becoming more widely accepted.
Plant Health Care has a comprehensive program of
biologicals that support greenhouse, nursery, turf, etc.
The web site contains award-winning educational materials
that explain soil biology etc really well.
Plant Health Care
I'm not familar with ironwood. But just about everywhere
one lives local plants exist which can be made into herbal
teas to control foliar diseases and boost plant health.
Finally, Serenade is a biological fungicide from AgraQuest
that is approved for organic production. It comes in a
package like most fungicides, with a label, with instructions
to mix, etc.. So it is probably the easiest sell to commercial
growers because this approach is like substituting organic
brand for chemical brand; it is familiar, and it has assurance.
The biological control organism, Bacillus subtilis, competes
with pathogens and more or less just takes over the leaf
surface and prevents disease.
Interestingly, that is the same thing compost teas do. Only
compost teas are working with dozens or hundreds of species
of beneficial microbes that offer an enormous diversity
Elijah Smith wrote:
> I'm sorta working with a nursery in the area (Hawaii) that is staffed
> by a pretty traditional crowd but is owned and run by a guy who's
> willing to try new things. So far, I'm turning the cuttings, etc into
> compost, trying to phase out vermiculite for the (locally available)
> cinder, brewing compost tea, etc. I've heard, mostly through anecdotes
> and biodynamics texts, that silica is an effective remedy for mildew &
> fungus diseases. Currently, the nursery is using some sorta biocide
> spray for this (we're on the wet side of the island). When the
> ironwood discussion came up, Robyn posted a quick and simply ironwood
> tea recipe for fungal spray. This would be cool, cheap, local, etc
> but I need some sorta reference to back up these claims. Does anyone
> know of any studies, reports, books, etc to that effect?
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