gardener's hand holding red maple leaf diseased of powdery mildew, fungal disease of maple trees.

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 gardener's hand holding red trees pathogenic phytopatholog spots concept trees