Cell suspensions of Xenorhabdus nematophila and its metabolites from Steinernema pakistanense (strain HAM-10) were lethal to G. mellonella larvae and vine mealy bug. Different experiments on penetration of cells, time of exposure, cell suspension in broth and water and serial dilutions of bacterial cell were conducted. X. nematophila suspension containing 4.0× 10⁴ bacterial cell/ml showed penetration power within 6 min in G. mellonella and vine mealy bug. Cell in broth was more effective than cell in water suspension. At different time interval maximum mortality 97% and 95% was assessed after 24-48 h exposure of cell in broth and water suspension against G. mellonella and 95% and 77% in vine mealy bug. The supernatant and residue+ water also showed similar lethal effects. The LD₅₀ value of different doses of bacterial concentration was found to be 4.02, 19.135 bacterial cell/ml, while probit regression equation were calculated as 3.98+ 0.41 x, 4.7+ 0.22 x against G. mellonella and vine mealy bug, respectively. The LT₅₀ value of different time interval of bacterial concentration was found to be 0.377 h and 11.8 h against G. mellonella and vine mealy bug, respectively.