One of the infected leaves I have removed from my Masdevallia decumana to send into the Advisory Service at RHS Garden Wisley. The Royal Horticultural Society offer a free advisory service, which includes identifying pests and diseases, to all their members.

yellowing orchid leaves, yellowing leaves miniature orchid, masdevallia decumana leaf damage, masdevallia decumana yellowing of leaves, yellow leaves masdevallia decumana, marked leaves masdevallia decumana, masdevallia decumana leaf damage, masdevallia decumana unwell, masdevallia decumana black spots on leaves, masdevallia decumana spots on leaves, fungal leaf spot, fungal leaf spot masdevallia decumana, colletotrichum, colletotrichum leaf spot, colletotrichum leaf spot masdevallia decumana,