Biocontrol of Alternaria leaf spot of Vicia faba using antagonistic fungi

In dual culture, all the three antagonists, viz. Trichoderma vireus Milter, Giddens and Foster, Trichoderma harzianum Rifai and Trichoderma viriilc Pers. ex. Fr. overgrew the colony of Alternaria alternate (Fries) Keissler but T. viride parasitized the test fungus earliest. T. viride exhibited highest growth rate in mono and dual culture. Studies on hyphal interaction between antagonist and test fungus revealed disorganization of protoplasmic content and lysis of hosl hyphae. T. viride exhibited 36.33 per cent disease control and proved superior in providing protection against Alternaria leaf spot of Vicia faba in field than T. vireus and T. harziauum.