Trichoderma asperellum (NST-009): A Possible Thai Native Antagonistic Fungus for Managing White Root Disease of Rubber Trees (Hevea brasiliensis)

Background: Rigidoporus microporus causes white root disease, which is one of the most harmful diseases in rubber trees in Thailand. The objectives of this study were to determine the efficacy of T. asperellum NST-009 and its antifungal metabolite in inhibiting R. microporus mycelial development and efficacy of T. asperellum NST-009 in controlling white root disease of rubber trees in an open-field house experiment. Methods: Four native strains of T. asperellum from Nakhon Si Thammarat Province and a commercial strain of Thailand were used in this study. This study was conducted at Agricultural Microbial Production and Service Center, Walailak University, Nakhon Si Thammarat, Thailand, during the period 2017-2020. Result: T. asperellum NST-009 significantly inhibited R. microporus mycelial growth by 77.07% in vitro and its antifungal metabolite from the culture filtrate of T. asperellum NST-009 inhibited mycelial growth by 92.31%. T. asperellum NST-009 reduced the disease severity index by 76.38% in the open-field house experiment compared to the inoculated control. Furthermore, T. asperellum NST-009 was found to survive in rhizosphere soil at 4.50 × 105 CFU/g soil and colonized the roots at 100.00%.