Plz help!! Masd "Cheryl Shohan" has perfectly round, tiny black spots

[sbriz]

Hello! This is my first time posting and I need some advice, please. My Masdevallia "Cheryl Shohan" has started to develop tiny dark, blackish, perfectly round spots on its leaves. Looks like something might be boring thru the underside of the leaves, but haven't spotted anything. Used an insecticide w/neems oil on it and water it about twice a week. It is kept on antique pillow or shoe rack with other orchids in a west window in my home. Circulation is standard central heat/air. My home is about 80 years old and on pier and beam. Any advice? I recently moved this plant from my bathroom, where it sat in a northern window--moved it because the bathroom tends to be colder. Please help--I'm fairly new to growing different types of orchids other than phals, but have recently added oncidiums, cattleyas, a vanda, and dendrochilum. Thanks.
-Susan

[Ross]

Without seeing a picture, I can only guess the spots are fungus-related - not insects. A spray of Thiomyl wouldn't hurt anything and might help stop the spread if that is what is going on. Can you post a picture? Rest of your culture seems reasonable. Cold temps aren't necessarily a problem for most Masdies, but low light and stale air might be. I grow mine in a south window under constant (24/7) fans (2 of them). Temps get close to 60 degrees F at night and maybe high 60s on a good day during the day. Perfect for most of these guys. But higher light and really good breeze are musts. I also water more often (a bi-product of constant air movement). I water every other day as a minimum. Low fertilizer (like hardly any at all). Leaves will pleat severely if not enough water in mix, and flower spikes will bolt prematurely.