At Jyothy Institute of Technology (Bangalore) farm, infected leaves were found as shown below

On both sides of leaf surface numerous small, superficial and blackish distinct tar like spots which surrounded by yellow zone were observed. Along with the tar spots, there was light yellowish stroma and mats of hyphae of fungus were found on the upper surface of leaves. They were observed under foldscope and spores were found.

• Spores of Rhystima
• 
• Spores of Rhystima with lactophenol cotton blue

It was tar leaf spots. This caused by Rhytisma acerinum fungus.