Biological Control of Fungal Phytopathogens with Trichoderma harzianum and Its Fungicidal Compatibility

Excessive synthetic fungicide use reduces soil's antagonistic population, allowing soil-borne plant pathogens to cause significant global losses. Despite high fungicide application, plant diseases persist, harming the ecosystem. Trichoderma spp, an eco-friendly plant symbiont, can serve as an alternative biocontrol agent. This study evaluated Trichoderma harzianum's antagonistic effect against fungal pathogens and its compatibility with fungicides under in-vitro using a Completely Randomized Design with four replications per treatment. Trichoderma harzianum showed high antagonistic activity for Alternaria brassicicola (70.35%), Fusarium solani (70.82%), Helminthosporium sorokinana (66.55%), Rhizoctonia solani (78.58%), Sclerotium rolfsii (92.53%). Among the tested fungicides, Copper oxychloride and Mancoxeb at 400 ppm showed maximum compatibility with growth inhibition percent (GIP) of 2.41% and 7.91%, respectively, after 60 hours of incubation. Fungicides viz., Carbendazim, Hexaconazole, and Carbendazim+Mancozeb at all concentrations aren’t compatible with 100% GIP throughout the experiment, and for Metalaxyl+Mancozeb, high growth inhibition percent was observed ranging from 42.77% to 78.40% making it incompatible. In integrated disease management, compatible fungicides at recommended doses can be used in combination with T. harzianum.