What is an orchid fungus?

Orchid fungi are parasitic or saprophytic organisms that live without chlorophyll. The mold on the food we see every day, the koji for making wine, the mushrooms on the table and so on all belong to fungi. It has no roots, leaves and vascular bundles, different from higher plants, but can reproduce asexually and sexually, and most of them have hyphae (branched filaments) and are different from bacteria. There are about 30 genera and 60 species of fungi harmful to orchids. The more important ones are Collectotrichum, Sclerotium, Botrytis, Phytophthora, Rhizoctonia, Fusarum and so on.