The attack of pathogen Erysiphe polygoni is marked by minute discoloured patches from which a powdery mass radiates on all sides. These floury white patches first appear on both surfaces of leaves, tendrils, pods and stem. When the disease becomes severe, large areas on the aerial part of host are covered with the floury patches. Ultimately the disease is easily recognized by white powdery coating on all over the plant that contains enormous conidia produced by the fungus.