ژاله زرگرزاده - M.Sc. Student, Department of Plant Pathology, College of Agriculture, Tarbiat Modarres University, Tehran, Iran
ابراهیم محمدی گل تپه - Prof., Department of Plant Pathology, College of Agriculture,Tarbiat Modarres University, Tehren, Iran (E-mail: emgoltapeh@yahoo.com)
یونس رضایی دانش - Assistant Prof., Department of Plant Protection, Faculty of Agriculture, Urmia University, Urmia, Iran
مصطفی مهرپرور - M.Sc. Student, Department of Plant Pathology, College of Agriculture, Tarbiat Modarres University, Tehran, Iran

Different species of Trichoderma especially T. harzianum (Th۲ biotype in Europe and Th۴ in America) considered as causal agent of green mould disease on button mushroom (Agaricus bisporus) casing beds. In this study, ۱۰۰ fungal isolates were collected and purified from different mushroom growing units in Tehran province and Urmia (NW Iran). Totally, ۶۰ isolates of T. harzianum, ۲۷ isolates of T. virens, seven isolates of T. hamatum and six isolates of T. inhamatum were morphologically identified. The main infectious agent was T. harzianum. Specific primers were used for identification of different biotypes. 

distribution, molecular identification, Optimum temperature, Th۲ and Th۴ biotypes