Viewing post #867184 by shadytrake

hawkarica said:Both copper and sulfur are natural fungicides and can be used on orchids. So can the combination called coppersulfide. Pyrethrins are insecticides derived naturally from chrysanthemum flowers. They act as nerve agents to paralyze the pests. No problem using them on orchids either.
Jim

Except for Dendrobiums!! Copper fungicides defoliate dendrobiums and deform the flowers.

Also, many fungicides sprayed during active bloom growth can deform flowers. Be sure to read the labels to avoid deformities.

I had to spray (no choice) and even though I used the ones that stated no deformities to flowers, I got several deformed flowers.

This is the best short reference sheet for information. Look at page 36. Great cheat sheet.

http://www.phelpsfarm.com/Orch...

and this one

http://staugorchidsociety.org/...