powdery mildew on maple leaves. white spots of powdery mildew on maple tree. powdery mildew, fungal disease. pathogenic fungi,

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 leaves spots tree disease pathogenic trees concept