The Application of Trichoderma asperellum Powder to Control Sheath Blight Disease of Rice Caused by Rhizoctonia solani

Abstract

The application of Trichoderma powder to control sheath blight disease of rice caused by Rhizoctonia solani was studied. Trichoderma sp. was isolated from soil samples in fruit crop cultivation area at Chanthaburi province. Trichoderma sp. (MC2560) was morphologically and molecularly identified. Molecular identification was carried out using ITS4 and ITS5 primers. The homology level of the isolate was checked using BLAST program. The isolate was identified as Trichoderma asperellum QT22046 accession number KY225608 with a homology level of 98.58%. T. asperellum was tested for antagonistic activities using dual culture method against R. solani on Potato Dextrose Agar (PDA). T. asperellum had shown a growth inhibition of R. solani at 42.10% and T. asperellum mycelium overgrown on R. solani colony at 0.56 cm per day. Growth of T. asperellum on PDA at 25-30°C had the fastest growth and colony full covering on culture media within 3 days, in contrast at 40°C showed non-growing. Efficacy of T. asperellum powder as biocontrol in controlling sheath blight disease of rice was examined under greenhouse condition. T. asperellum powder was suspended in buffer (0.2% carboxyl methyl cellulose, 0.5% chitosan and 1.0% tween80) with talcum as carrier. Inoculation with R. solani on rice plants variety RD41 at 50 days old in greenhouse was prepared by mix of mycelium disc with sterile paddy and husk, put in straw paper bag wrapping with aluminum net and placed between rice stems at water level. After that, T. asperellum with talcum was applied by spraying on the rice plants. Results showed that disease incidence of plants treated with T. asperellum powder at 40 g per 20 L was decrease at 42.01% and 37.31% after spraying 14 and 21 days, respectively, compared with control (inoculated rice plant without spraying).