The white button mushroom requires a casing layer that has specific physicochemical and microbiological properties which stimulate and promote the initiation of sporophore. However, slight attention has been given to the importance of microbial properties of casing materials. Casing layer supports beneficial microbial population that release growth stimulants, which are reportedly involved in stimulating the initiation of pin heads. This Study describe the effects of Pseudomonas spp. on the yield and nutritional value of cultivated mushroom (Agaricus bisporus) and investigate the viability of Pseudomonas spp. and bacterial population in general during mushroom picking flushes.