BACKGROUNDDiseases caused by Fusarium pathogens lead to significant yield losses on many economically important crops. The purpose of this study was to evaluate the antagonistic capability and chemical profile of the bioagent Trichoderma asperellum against several Fusarium strains. The efficacy of this strain in reducing Fusarium‐root rot disease in dry bean was also examined.RESULTSThe T. asperellum strain was identified based on sequencing the ITS and tef1 gen regions of ribosomal DNA. Dual cultural assay demonstrated their antagonistic activity against the studied Fusarium strains due to the probable combination of competition, mycoparasitism and antibiosis. This strain was positive for cellulase, chitinase and protease activity. The crude extracts of T. asperellum significantly suppressed the growth of the tested Fusarium strains with inhibition zones values ranged from 7.3 to 19.7 mm and minimum inhibitory concentration (MIC) values ranged from 0.15 to 1.42 mg mL‐1. The GC‐MS analyses of cell free supernatant and mycelial biomass of T. asperellum showed the presence of 27 and 21 compounds, respectively. The main compounds responsible for the bioactivity were Butylated Hydroxytoluene, Hexadecanoic acid, 9‐Octadecenoic acid, Ergosterol and Hexadecanoic acid, ethyl ester. Trichoderma asperellum significantly increased plant emergence and reduced root rot caused by F. solani in dry bean grown under greenhouse and field trials. Further, plant biomass and dry bean yield were higher in T. asperellum‐treated plants than in control plants.CONCLUSIONTrichoderma asperellum was highly effective, through various mechanisms, against Fusarium strains especially F. solani which causes root rot in dry bean.This article is protected by copyright. All rights reserved.