Evaluation of Local Isolates of Trichoderma Spp. against Black Root Rot (Fusarium solani) on Faba Bean

Abstract

Faba bean ( Vicia fabae L.) is one of the most important pulse crops in Ethiopia and is now cultivated on large areas in many countries. In most growing areas, however, the production of the crop is constrained by several disease infections, including fungal diseases. Black root rot caused by Fusarium solani is the most destructive disease of faba bean. The antagonistic potentials of locally isolated Trichoderma spp. from rhizosphere soils of faba bean plants in the highlands of northeastern Ethiopia were evaluated against F. solani, responsible for black root rot. All isolates of Trichoderma spp. had strong biological control activity against F. solani in vitro as well as in vivo pot experiment. Under dual culture, the percentage of mycelial growth inhibition of F. solani by the Trichoderma ranged from 33.9 to 67.0%. The highest (67.0%) inhibition was obtained from isolate TS036, while the lowest (33.9%) by isolate TS015. Pathogen-inoculated faba bean plants grown in pots that were treated with antagonists had taller plant heights and biomass than the Trichoderma untreated control inoculated with F. solani. The Trichoderma isolates significantly reduced black root rot severity on faba bean seedlings with disease reduction ranging from 64.4 to 74.6% over control. Use of Trichoderma species can be a potential source of biological control agents for the management of black root rot in faba beans grown in the region. Hence, the potential Trichoderma isolates under field condition might used as a components in the integrated management of F. solani that caused faba bean black root rot in the highlands of northeastern Ethiopia.