There are two basic principles, mentioned by other post of this thread: air
circulation and humidity control and rotation (including taking out
volunteers, removing crop residues to the compost heap).
Resistence to fungal problems on leaves is greatly reduced by regularly
applying organic foliar fertililzers prepared from compost--the greater
variety of organic matter in the compost, the better the foliar fertilizer
in promoting diverse, balanced fungal populations in the phylosphere--this
is the real key to contolling leaf fungus. Our favorite formula is
"Supermagro", an fermented fertilizer (ie produced anerobically) invented
by a Brasilian organic farmer named Magro. Trace minerals are included in
the formula, according to need, creating natural chelates. Weekly foliar
application is recommended in vegies. Staring this process as soon as the
seedlings are set out seems to prevent all sorts of problems, including PM.
Michele Gale-Sinex writes:
>The Pacific Agri-Food Research Center in BC reports the use of
>100 ppm soluble silicon in nutrient feed (in the form of potassium or
>sodium silicate) as a control for powdery mildew (hereafter PM) in
>cukes:
>
Various herbs achieve control, perhaps because, at least in part, of their
Si content. Our standard cure for powedery mildew in vegies is a the
classic mixture of mashed garlic and onion in a neutral soap base (as
adherent). This is what works best (after contolling humidity conditions).
Another source for Si is Equicetum tea, which is also used in Mexico as a
fungistat, though I don't know how it works for PM.
Chamomile is essentially for bacterial control but bacteria seem to be
involved in PM ecology somehow; people apply itto PM with good results.
We apply sulphur in the form of "caldo sulfocalcico" "sulfocalcic soup",
also a classic recipe from 19th century Europe. This is not recommended for
cukes after flowering has begun. Although it accepted as organic, I
consider it a bit toxic.
Certainly what Diane says about "plants out of place" is true; but most
vegetable in our gardens are essentially "plants our of place". As with
all these tiype of problems. especially fungi, knowing the trace mineral
situation in you soils and plants is a great help in controlling al sorts
of problems.
Actually, there are other interesting experiences re fungus and pest
control generally--amazing what farmers come up with once they kick
dependence on synthetic poisons and extension agents and start
experimenting for themselves. Hope this is helpful.
Ronald Nigh
Dana, A.C.
Mexico, D.F. & San Cristóbal de Las Casas, Chiapas
Tel. y FAX 525-666-73-66 (DF)
529-678-72-15 (Chiapas)
danamex@mail.internet.com.mx
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