Green mold disease caused by Trichoderma species is a serious problem for Lingzhi growers. Recently, green mold disease of lingzhi mushroom caused by unknown species of Trichoderma was found in lingzhi farm at Songkhla province, Southern Thailand. Therefore, the aim of this research was to identify the species of the causal agent. Trichoderma species were collected from G. lingzhi spawn to isolate and identify based on morphological characteristics and DNA sequence of the internal transcribed spacer regions (ITS). The phylogenetic tree was constructed by maximum likelihood analysis base on the ITS sequence comparison with sequences of ex-type culture from closely related taxa. A total of three Trichoderma species were identified as T. harzianum, T. pleuroticola and T. reesei. T. pleuroticola and T. reesei are the first report of green mold disease of G. lingzhi in Thailand.
