Jacqueline Cahoon wrote:
I was listening to NPR this morning in the car, a program called The
People's Pharmacy. They were discussing the pharmacological use of
cornmeal to treat fungal infections. The called who introduced the
topic mentioned that he also uses cornmeal worked into the soil
around
his roses to prevent blackspot. Has anyone heard of this before?

The Stephenville A&M Research & Extension Center discovered
fungus-fighting properties in cornmeal, but not for application directly
to any plant; rather it is applied to soil. Several additional studies
have extended this research, mainly for use in developing organic food
crops (peanuts, potatos, soybeans, cucumbers, etc) for fighting crop
pathogens without chemical intervention. Much of what has been discovered
has obvious applicability to ornamental gardening, though gardeners have
misunderstood some of it..

400 to 800 pounds of cornmeal is applied to each acre of soil (or ten to
twenty pounds per 1000 square feet). The cornmeal when wetted by normal
irrigation (or rainfall) begins to feed beneficial microorganisms &
especially helpful mycoparasite Trichoderma spp, which are mycoparasites,
meaning helpful fungi that parasitize & feed upon pathogenic fungi such as
Sclerotinia (Stalk Rot), Sclerotium (tropical stem rot), Aspergillis nigre
(black mold), & Rhizoctonia solani (black scurf, lower-stem decay, &
root-rot). Cornmeal application directly to leaves has no effect, but
changing the nutrient content of the soil to enhance positive
microorganisms does.

This method restrains harmful funguses from getting started & works best
in purely organic growing conditions, by encouraging beneficial funguses.
If fungicidal chemicals are also being applied to plants, that defeats the
value of the cornmeal since fungicides also discourage beneficial fungi.

Misunderstanding rumors of this research has led to many on-line
discussions of cornmeal to control blackspot or to be dusted over plants
afflicted with any kind of mildew or fungus. Mostly these discussions are
ill informed & come close to being garden myths. Yet there is good reason
to speculate that cornmeal added to the soil may help prevent ALL harmful
soil-born funguses, including such things as oak wilt & possibly blackspot
before it gets to the roses, even though the evidence isn't all in. It
certainly causes no harm to try it as a blackspot preventative in the
soil, since cornmeal has no negative side-effects & even functions as a
tepid fertilizer, & ANYthing that replaces the use of fungicides will help
beneficial funguses do their natural work of improving the overall health
of a garden.

-paghat the ratgirl
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"History, I believe, furnishes no example of a priest-ridden
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