powdery mildew, fungal disease on maple trees. white spots on maple tree. pathogenic fungi, phytopathology, plant diseases concept

maple tree leaf white plant disease fungi pathogen pathology phytopathology spot diseased norway uncinula powdery mildew sawadaea tulasnei acer platanoides leaves struck fungal diseases problem parasite flora infected deciduous mushroom illness foliage botany green floral nature branch mealy trees spots tree pathogenic concept leaves