during the study of powdery mildew related to erysiphaceae family from abardeh region in mashhad (khorasan-e-razavi province), one species of rose (rosa persica michx.ex juss, summer 2006) with symptoms of powdery mildew was collected. the symptoms observed with the naked eye including the dense cottony shape mycelia infected the leaf surfaces as well as some parts of the stem. mycelia were den...