Trichoderma Isolates Against Abiotic Stresses and Management of Collar rot of Lentil (Lens culinaris L.) Caused by Sclerotium rolfsii

A total of 30 native Trichoderma isolates were collected from the Agricultural Research Station, Ummedganj- Kota, Rajasthan, India. Out of which 9 native isolates were evaluated for bio-efficacy against Sclerotium rolfsii. Isolate ARS K-21 exhibited maximum inhibition (89.26%), followed by ARS K-11 (83.70%) in dual culture. Subsequent evaluations revealed the compatibility of efficient isolate ARS K-21 with various bio botanicals displaying minimum inhibition with Vermiwash (1.11–3.70%) followed by Beejamarat (0.38–15.92%) and Brahmastra (7.78–19.68%), while ARS K-11 displayed compatibility only with Dasparni ark with a minimum inhibition of 1.11–3.70%. Assessment of abiotic stress tolerance of the isolates revealed that most isolates thrived at 200 mM and 400 mM NaCl salt concentrations, with ARS K-21 and ARS K-24 demonstrating moderate growth levels across higher concentrations, except at 1200 mM. Optimal growth of the isolates occurred at 25 and 30 °C, with deviations leading to growth inhibition. Isolates ARS K-1, ARS K-11, ARS K-12 and ARS K-21 exhibited resilience to temperature extremes. ARS K-21 has shown exceptional growth proficiency across a wide pH spectrum (pH 5 to 8.5) followed by ARS K- 24, highlighting their versatility. Mass multiplication of efficient isolate ARS K-21 enriched with vermicompost led to the standardization of a dosage (30 g/kg soil) for managing collar rot in lentil crops at 5 g inoculum per kg soil of S. rolfsii.