S. sclerotiorum is a strong and resting soil pathogen with high resistance to synthetic fungicides. The biocontrol agent Trichoderma spp.alone provides moderate control of this fungus. In present study, Potassium tartrate, ascorbic acid, folic acid, thiamine and micronutrients mixture were used to improve the number of spores, fresh and dry weights, crude extracts, volatile compounds, and secondary metabolites produced by four isolates of Trichoderma against pathogen. A onetime amendment of thiamine (0.1%) or micronutrients mixture improves the antagonism efficacy of the most Trichoderma isolates showing complete prevention of pathogen growth and inhibition of sclerotia formation.