potato leaf attacked by alternaria solani

agricultural agriculture alternaria alternariosis attack attacked barley black cercle cereals circles cultivated dark death disease diseased food fungi fungicide infected leaf line loss malva malvacearum melodogyne natural nature necrosis nematods nuda orange ornamental parasite pathogen pathology pattern pesticide phytopathology plant point potato problem showing solani solanion solanum specific spore spp symptom symptoms threat tomato tuber tuberosum