In vitro Evaluation of Trichoderma harzianum (Th4d) for the Management of Foliar and Soil Borne Pathogens of Castor

Abstract

The present study evaluated the biocontrol efficacy of Trichoderma harzianum isolate Th4d against key fungal pathogens affecting castor (Ricinus communis), including Fusarium oxysporum f. sp. ricini, Macrophomina phaseolina and Amphobotrys ricini. Through the use of the poisoned food technique, Th4d consistently shown better antifungal effectiveness than chemical fungicides in in vitro, dramatically lowering mycelial growth across infections. It was able to successfully suppress the growth of F. oxysporum (54.44 per cent) and attain a maximum inhibition of 76.66 per cent against A. ricini and 56.66 per cent against M. phaseolina. As established by seedling tests by paper towel method, Th4d increases biomass, seed vigor and root and shoot length while lowering the incidence of disease. Other in vitro evaluation method including detachable capsule further shown that Th4d is just as effective as Propiconazole at suppressing gray mold. The broad-spectrum antagonistic ability of Th4d and its potential as an environmentally benign substitute for synthetic fungicides in the treatment of castor disease are highlighted by these findings.