Black Spot Fungus (Phal) Contagion Risk
 

Wondering if close-by plants are at risk. Is common "black spot" the correct diagnosis (Anthracnose)? Thank you.

I’m not sure about risk to other plants. Some of my plants have developed this, it seems to set in when they are kept colder than they want to be for an extended period. If I catch it early and warm them up, they make a full recovery. But if I leave it too long and it gets into the stem, I usually lose the plant.

I haven’t had issues with it spreading when I bring the plants into warmer areas, but I also make sure there’s no water on the leaves or physical contact.

Thank you. Your answer makes sense. The plant in question is (I think) a "Dori." I guess I was mistaken that Doritanopsis tolerate lower night temps than straight phals. I should have checked. I've been allowing that room to drop to 55 at night because it's mostly paphs and miltoniopsis in there. Although there is significant dark discoloration in the leaves, it seems to be inside the leaves - no lesions on the surface, upper or lower. True of your plants as well? I've also noticed that spike development is quite slow. This must be it. Easy fix. Thanks again.

I have mostly NOID complex hybrids. I have a bunch that I acquire in the summer and end up keeping outside. When nights start getting into the 40s and days don’t get warmer than the 60s some start getting this type of damage. If I bring them in the house (70s), the progression stops although the affected leaves stay “ugly”.

I have lost a few indoor Phalaenopsis on windowsills and I suspect that even 60s were too low for them so I try to stay away from hybrids with a lot of “hot” growers in their background if I’m buying ID’d plants.