• Botrytis: Petal spotting.
• Virus (Cymbidium mosaic, Odontoglossum ring spot, and others): A wide range of symptoms may result from virus infection, including dark brown or purple spotting on foliage. Spotting sometimes closely mimics infection by fungi or bacteria. Some of the most damaging orchid viruses are easily transmitted by routine handling of the plants, so the orchid collector should become familiar with special handling procedures that avoid transmission of viruses.