white powdery mildew on cucumber plant

agriculture and biology blight cichoracearum closeup control cucumber cucumis danger disease diseased erysiphe farming flower foliar fuliginea fungi fungicide fungual fungus garden gardening green grow home infection infest leaf macro microorganism mildew mold mould nature outbreak parasite pathogen pathology pest pesticide phytopathologyl plague plant problem protection pustules repellent sativus science sphaerotheca spores spot summer symptoms terrace