Hello and I need to indentify the cause of these black spots on the leaves of Gramatophylum scriptum. I water 3 times a week, feed once every 2 weeks, temp. is a comfortable 75F. Any information is appreciated to solve the problem, such a beautiful plant!! I have attached 2 pictures to have an idea what these spots look like.
I'm not familiar with this species, but on most orchids, these types of spots are caused by mild fungal infections, which are usually controlled by improving ventilation (adding fans) wherever they are grown.
Systemic fungicides can also be used, but it's better to try and solve the problem without them.