ABSTRACT
The Pleurotus mushroom is generally called the oyster mushroom because the pileus or cap is shell-like, spatulate, and the stipe eccentric or lateral. The species of Pleurotus ostreatos (Jacq: Fr.) Kummer has been used as food or for medicinal purposes for a long time, and at present plays an important role as a commercial edible mushroom. More than 1000 species of the oyster mushroom have been described throughout the world, in more than 25 related genera. However, only approximately 50 valid species are recognized in the genus Pleurotus. 13 Pleurotus ostreatus (Jacq.: Fr.) Kummer is one of the best known among the oyster mushrooms. Other commonly cultivated species include: P. sajor-caju (Fries) Sing. (gray oyster mushroom or phoenix-tail mushroom), P. cystidiosus O.K. Miller (abalone mushroom), P. ostreatus var. florida nom. prov. Eger (white oyster mushroom), P. citrinopileatus Sing. (golden oyster-mushroom), P. flabellatus (Berk. and Br.) Sacc (pink oyster mushroom), and P. sapidus (Schulzer) Kalchbremer (black oyster mushroom). They belong to the family Tricholomataceae, order Agaricales, and class Basidiomycetes. They grow naturally mainly in the temperate zones or in the cooler seasons in subtropical areas on rotting trees such as oak, elm, maple, bass, poplar, holly, and laburnum. They have a fragrant odor and delicious flavor. However, Pleurotus has been reported as parasitic on several trees. 9 , 27 Species of Pleurotus, such as P. cornucopiae (Paul.: Pers.) Roll., P. cystidiosus, P ostreatus, P tuberregium (Fr.) Sing., are known to attack and consume living nematodes, through special structures named microdroplets, as reported by Barron and Thorn 2 and Hibbett and Thorn. 15
