Evaluation of the potential of Trichoderma viride in the control of fungal pathogens of Roselle (Hibiscus sabdariffa L.) in vitro

The potential of Trichoderma viride as a bio-control agent was evaluated in vitro against Roselle pathogens i.e. Phoma exigua, Fusariurn nygamai and Rhizoctonia solani [1] using the dual culture technique. Volatile and non-volatile inhibitors of Trichoderma were also evaluated for this purpose. T viride [2] was shown to have a marked inhibitory effect on the tested pathogens in vitro. Maximum inhibition occurred against P exigua, with 71.76% reduction in mycelial radial growth. The three pathogens, P exigua, F. nygamai and R. solani were also found to be susceptible to the volatile inhibitors produced by T viride, giving rise to growth inhibition of about 68% in each case. When T viride non-volatile metabolites were tested against the pathogens, maximum inhibition occurred against R. solani (73.95% mycelial growth inhibition), followed by P. exigua (37.17% inhibition). The inhibitory effect of the non-volatile metabolites on E nygamai was, however, minimal. (C) 2012 Elsevier Ltd. All rights reserved.