downy mildew on cantaloupe melon leaves in agriculture farm. pseudoperonospora cubensis. problems of

agriculture cantaloupe close closeup color cubensis cucumber damage damaged destroy disease diseased diseases downy farm field foliage fruit garden goutweed green hindrance infected infectious injury invasive kill killing leaf leaves masterwort melon mildew mold mould natural nature obstacle oomycota parasite pathogen pathogenic pathology plant plasmopara problems pseudoperonospora spot surface surfaces trouble