Dactylaria Leaf Spot -- Dactylaria humicola
Symptoms: Dactylaria leaf spot first appears as small, water-soaked areas on both surfaces of young leaves but symptoms are more severe on the lower surface. As the spots mature, they turn yellow to tan in color and commonly have sunken centers. Only the immature leaves of heart-leaf philodendron are susceptible to the pathogen.
Conditions Favoring Disease: This disease is favored during the summer months and occurs primarily on ground bed plantings of the host.
How Pathogen Survives/Disperses: The fungus survives in soil and spreads to plants grown in ground beds.
Photo and write up provided by Syngenta Professional Products