White cottony mass on rose (powdery mildew) caused by the fungus is the most common disease on roses during humid condition. Powdery mildew appears as a whitish powder, covering foliages (Fig. 1). A high number of developed reproductive structures (conidia) with mycelia threads harboring rose leaf can be seen directly by placing diseased leaf with Foldscope even without staining (Fig. 2). Structures that bear reproductive cells of fungus (conidiophore) can be seen without (Fig. 3), or with staining (Fig. 4).
Initial observation suggest that this fungus could be Podosphaera pannosa (conformation needs further detailed investigation)Initial observation on garden rose disease