Sorry about that. Does the infection start from the leaf tip and progress towards crown or how is it?. Does the description match with yours?. "This fungal disease infects the aerial portion of the plant. The leaves are most often attacked. Leaf tips turn brown beginning at the apex and proceeding toward the base. Dark brown or light gray patches develop, sometimes as concentric rings or as numerous dark bands across the leaf. The affected area is usually sharply defined and somewhat sunken, while the remainder of the leaf appears normal. Sporing bodies develop in the infected area."
if yes this is Anthracnose. you would need remove the infected leaves with a sterile instrument and then treat the plant with thiophanate methyl or mancozeb