rust fungi on pelargonium zonale

agriculture and bill biology closeup control crane cranesbill danger disease diseased farming flower fungal fungi fungicide fungual fungus garden gardening green grow home infection infest leaf macro microorganism mold mould nature parasite pathogen pathology pelargonii pelargonium pest pesticide phytopathology plague plant problem protection puccinia pustules repellent rust science spores spot summer symptoms terrace zonale zonalis