Field Evaluation of Trichoderma Isolates in the Biocontrol of Rhizome Rot Disease of Small Cardamom

Small cardamom (Elettaria cardamomum Maton), ... the Queen of Spices is au important spice crop cultivated on a large scale in the Western ghats of South India. Rhizome rot is a major disease caused by Rhizoctonia solani Kuhn in cardamom plantations. The disease occurs in a severe form during monsoon and results in heavy crop losses. In the present study, exotic and native isolates of Trichoderma viride Pers. Fr. and T.harzianum Rifai were tested against the pathogen under in vitro conditions. These isolates were further evaluated in disease-prone areas in the field. Results showed that all the isolates tested showed antagonistic activity through hyphal coiling, penetration and lysis of the hyphae of the pathogen besides inducing growth inhibition of the laller. Among the nine isolates tested in the field, eight were found effective in controlling the disease incidence. An exotic isolate of T. harzianum and a native isolate of T. viride were found to be most effective, the reduction in disease incidence being upto 52 to 69 per cent.