Mushrooms are large reproductive structures of edible fungi belonging to Basidiomycotina. They are non-green and spore-bearing fruiting bodies of fungi which produced above ground on soil or on its food source (substrate). Blue oyster mushroom (Hypsizygus ulmarius) is one of the important edible mushroom and it was introduced for commercial production for the first time in India by Indian Institute of Horticultural Research, Bangalore (KN). This work was done to study the Influence of substrate treatment methods on yield and yield parameters and to find out the best substrate treatment methods for maximum yield. | Effect of substrate treatment methods on blue oyster mushroom Hypsizygus ulmarius Bull. Fr. Redhead production