I am a bad bad gardener.
My phals look like the teenage kid working at the local greasy spoon restaurant. They have plant acne.
Actually, I noticed that the phals (and the dendrochilum) had been hit with something that caused pitted spots on the tops of the leaves. Some of the plants have interesting designs where the leaves were infected. I believe it to be contact related because a few leaves that were turned upside down had the problem on the bottom surface of the leaf.
The Cattleyas, Oncids, Cymbos, and other stuff seem to be unaffected. This crud really likes those nice succulent Phal leaves.
My suspected sources are:
The swamp cooler that I did not change the pads like I should and something bloomed on those nice moist aspen wood pads then got sucked into the greenhouse. I promise to keep a closer eye on the swamp cooler from now one. I promise (unless of course I get busy with something else and put it off until another day like I normally do).
Another possibility is that when I cleaned the greenhouse with the pressure washer something that normally would be on the concrete floor got into the air and settled on the leaves. The floor of a greenhouse is one of the dirtiest places on earth.
The third suspect was the bucket I use to mix fertilizer for the Dosamatic. I may (ok I used to take shortcuts) not have cleaned it up very well before I used it between waterings and something was growing in the cesspool of old fertilizer.
So, here is my question. I want to start a regular spraying of Physan, specially on the phals. I see where Ray recommends 1 tsp to a gallon for plant contact.
How often can I apply Physan to the plant leaves at this rate?
What would I see if I am applying it too often? (Leaves burning, flowers deformed, etc.)
Any other ideas of what I should do to prevent this crud from returning?
I am fanatical about cleaning up the dropped flowers and dead leaves in my greenhouse. I keep the humidity very high in the winter and as a result I get algae and moss growing under the benches and on the glass. I clean it up periodically but it does return.
Thanks, Gene