Hi, Bob,

Claude sent you in the right direction. Cinnamon is a great fungicide, and
is also of use in combatting rot. I'm a beleiver.

One word of caution, though. Do not dust an entire root system, or even the
whole plant. Use cinnamon on affected areas or on spots where you have cut
away a piece of the plant, for whatever reason. An effective way to use it
is either as an alcohol infusion or mixed with Elmer's Glue (which is not
toxic to orchids), both of which are discussed on Ray's help pages.

Diana