Don't know about the cornmeal, but blended up banana peels
do wonders for roses. Banana peels don't seem to get rid of
black spot, but they do produce some healthy looking leaves
and flowers.

Still haven't figured out where black spot comes from, how it
gets to where it gets.

http://forums.gardenweb.com/forums/l...946389907.html

Seems like most people report favorable results at that link.

Doing a search through google turns up quite a few links about it.
I searched:

cornmeal roses

Hope that helps. And thanks for the suggestion!

--
Jim Carlock
Please post replies to newsgroup.

"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?
What about cornmeal as a preventative to other fungal diseases?