Vigna mungo L. (black gram) is a summer pulse crop endemic to Central Asia. It is one of Pakistan's top five premium food beans and a highly cost-effective crop. Allelochemicals in Trianthema portulacastrum leaf extract effect and inhibit black gram germination rate, seedling length, fresh and dry biomass of seedling from low to high concentrations. The research revealed that in vitro leaf extract of black pigweed decrease the mash bean leaf germination percentage (34% to 6%), seedling length (10cm to 3cm), fresh biomass of seedling (2.4g to 0.94g), dry biomass (1.2g to 0.47g). Biological tool Pseudomonas (PF- 097) act as bioherbicide and as plant growth promoter agent (PGPR) to decrease the Trianthema portulacastrum allelopathic stress and to enhance the growth of black gram. The Pseudomonas (PF-097) PGPR addition in vitro experiment increased mash bean leaf germination (8-42%), seedling length (12-54%), and fresh biomass of seedling (8-17%) and dry biomass of seedling (0.47g-1.2g). In vivo experimental study revealed that whole plant material of black pigweed significantly suppress the shoot length (46cm to 18cm), shoot fresh biomass (2.6g to 0.66g) and shoot dry biomass (1.31g to 0.33g) and Pseudomonas (PF-097) PGPR incorporation in vivo experminet significantly increased the shoot length (4% to 12%), shoot fresh biomass (18% to 35%), shoot dry biomass (17% to 35%).  Physiological activity of Catalase and peroxidase considerably increased in negative treatments amended with only T. portulacastrum and decreased in positive treatments by using biological agent Pseudomonas spp (PF- 097). By the amendment of Pseudomonas (PF- 097) protein content of mash bean seedling was significantly increased in positive treatments as compared to negative treatments.