Field experiments of a 2% W.P. Trichoderma viride (Strain No. BHU-2953, Accession No. NAIMCC-F-02976) formulation were conducted at experimental farms of Banaras Hindu University, Varanasi and SASRD, Nagaland University, Medziphema. The experiments were conducted in two seasons during 2007-08 & 2008-09 to test the bioefficacy of the formulation against the tomato wilt pathogen, Fusarium oxysporum and chilli damping-off pathogen, Pythium aphanidermatum. The formulation was applied as seed treatment and furrow application. The results revealed that the seed and furrow application of the formulation significantly reduced the wilt disease of tomato and damping-off of chilli. The yields of tomato and chilli were also significantly enhanced. Further, the formulation did not have any phyto-toxic effect either on tomato or chilli plants at all the doses levels tested for field bio-efficacy. The T. viride formulation also did not have any adverse effect on the beneficial rhizospheric microbes, like Arbuscular Mycorrhizae (Glomus spp.) in tomato and chilli rhizosphere at all dosages as confirmed with microscopic observations. Based on the above findings, the T. viride 2% W.P. formulation is found safe and effective for using as an efficient and ecologically-safe alternative to chemical fungicides for the management of wilt of tomato and damping-off of chilli as well as for obtaining higher yields.