Efficacy of Trichoderma-fortified compost in controlling soil-borne diseases of bush bean (Phaseolus vulgaris L.) and sustainable crop production

An attempt was made to evaluate the effect of Trichoderma-fortified composts in controlling major soil-borne diseases of bush bean at field condition. A series of preliminary trials were conducted to select the virulent isolates of the test pathogens (Fusarium oxysporum f. sp. phaseoli, Rhizoctonia solani and Sclerotium rolfsii) against the susceptible bush bean variety (BARI Jharsheem-1). On the basis of screening, among the 20 isolates of Trichoderma harzianum, Chan-6 isolate was found to be the most effective in inhibiting the radial growth (83.33, 79.44 and 81.11%) of F. oxysporum f. sp. phaseoli, R. solani and S. rolfsii, respectively. The most effective antagonist isolate Chan-6 was selected for inoculum preparation with colonized wheat grains and mixed with 90 days decomposed different composting substrates like cow dung, saw dust, rice straw, water hyacinth and poultry manure. Significantly, the highest 75.70% reduction of seedling mortality was achieved by the T. harzianum fortified compost with poultry manure treatment (T7) and superior to all other treatments. Similarly, the highest reduction of diseases were achieved with the treatment T7 which was followed by the treatment T4. All the T. harzianum fortified compost treatment significantly increased the pod yield (64.77-218.18%). T. harzianum fortified compost suppressed the soil-borne pathogens and also enhanced soil fertility by adding organic matter.