Dendrobium laevifolium spots on leaves?

[jason woodrue]

Hi,

My Dendrobium laevifolium has spots on the leaves. all the leaves seem to be affected by this to varying degree. Am i growing to warm? Humidity too low?

sometimes the black little spot is a depression and sometimes it is raised - almost looking like black scale, but more often it is sunk into the leaf. i have tried to remove the raised bumps but they do not come off. it kindof reminds me of how some oncidiums are prone to leaf spotting.
Other than the spots, the plant seems fairly healthy and is putting out nice new growths!

your thoughts?