The last thing I'd do is "step" on someone's toes! So.... RD-20 is now SA-20 made by Southern Agricultural Insecticides, Inc. I guess they changed the name to be more in line with the company name???????? Anyway, it is EXACTLY the same formulation as its cousin Physan 20 and used EXACTLY the same way. The company that markets Physan 20 is on the west coast, Maril Products Inc. During the summer, I hang my phals outside from my deck overhang and because they are under a large oak tree, I spray them and the flowers frequently (couple of times a month) because of the mildewv problem from the tree. I'm not completely convinced that it is the chemical that causes the spots but just water on the flowers. I say this because listed in the product instructions for use is the following:

"Botrytis Petal Blight: During cool weather, spray plants, flowers and under benches at first sign of spotting on flowers. Normally, weekly
sprayings will greatly reduce or eliminate the botrytis spotting. Use 1 tsp. of R-D-20 Greenhouse Disinfectant per 3 gallons of water."


It also goes on to say that the use as a preventative maintenance is:

"Adult Plants: Spray any time disease is evident with a solution of 2 tsp. R-D-20 Greenhouse Disinfectant per gallon of water. Spray once per
month as preventative maintenance"

Anyway, I post this not to start an argument or get anyone's nose out of joint. I use SA-20 on a regular basis as do many commercial grows who add it to their misting/watering system and have never had a problem. BUT, you MUST use it as directed for the use as: GREENHOUSE DISINFECTANT FOR ORCHIDS & ORNAMENTALS FOR USE AGAINST FUNGAL, BACTERIAL, ALGAL AND VIRAL PLANT PATHOGENS AND THEIR ODORS......
Greenhouse Disinfectant is a Concentrate and Must be Diluted Before Use