top view of powdery mildew on on salvia golovinomyces biocellatu

agriculture and biocellatus biology closeup control danger disease diseased downy farming foliar fungi fungicide fungual fungus garden gardening golovinomyces green grow home infection infest leaf macro microorganism mildew mold mould nature outbreak parasite pathogen pathology pest pesticide phytopathology plague plant problem protection pustules repellent sage salvia science spores spot summer symptoms terrace