Solanum tuberosum L. (Potato) belongs to the family Solanaceae with its origins traced back to the Peruvian and Bolivian Andes of South America. It has lot of demand as a staple food throughout the world. There are mainly two important threats to potato after cultivation, that includes Pythium aphanidermatum and root knot nematode. These two threats completely destroy the production of potato crop thereby reducing yield and causing an economical loss to the farmers. Despite the utilities of this crop, efforts weren't made to control these diseases which led to farmers using harmful chemical pesticides. Trichoderma as biological control agents have been widely used against many plant pathogens. Paecilomyces lilacinus, grows as a facultative parasite on nematode eggs and has been used to manage Meloidogyne spp. In present investigation “Kufri Jyoti” cultivar of Potato was used. The experiment was conducted with replicated randomized design. The soil used for experimentation was Garden soil and was autoclave sterilized and then filled into pots of size 20 x 20 x 25 cm, consisting of 3 kg soil capacity. Four sets were used for experimentation. Each set included one control and three replicates. Experimentation was carried out to evaluate the effect of pathogens before and after inoculation of antagonistic fungus in pot culture experiment. The plants were assessed for morphological parameters and biochemical contents. Statistical analysis of the results was found strongly significant.