The use of biological agents is becoming an increasingly important alternative to chemical control against insects, weeds and diseases in agriculture. The success of this method depends on the nature antagonistic characters and the mechanisms of action of microorganism. Fungi are the most important biological agents against plant pathogens. Trichoderma species are common filamentous imperfect fungi. The mycoparasite ability of Trichoderma species against some economically important plant pathogens allows for the development of biocontrol strategies. In this research, the effect of biocontrol of Trichoderma species on some plant pathogens was investigated. The results showed a direct inhibition of the pathogenic microorganisms by Trichoderma species. Hence Trichoderma species can be considered as biocontrol agents for control of some plant pathogens.
