We have investigated the role of the thermo-photoperiodic condition of maternal generation in diapause induction of Trichogramma chilonis (Ishii) (Hymenoptera: Trichogrammatidae) lab strain. To test the maternal effect, two lines of T. chilonis lab strain were generated by rearing them for one generation at: (1) 15 °C with L:D-12:12 (15F-112) and (2) 15 °C with L:D-20:4 (15F-120). The laboratory strain reared at 15 °C with L:D-12:12 for 65 generations (15F-6512) was used as the control (acclimatized strain) due to its proven diapausing capacity. The 15F-120 line failed to undergo diapause, though healthy pre-pupae were formed at the pre-storage condition (at 10 °C with L:D- 8:16 and RH-60-70%). However, 15F-112 line could successfully complete all the phases of diapause and was comparable with the control batch. Considering 50% adult emergence and minimum 3 days of longevity, 125 days of storage could be achieved. From our current study, we conclude that diapause can be induced in T. chilonis lab strain by providing appropriate thermo-photoperiod to their maternal generation (for a single generation) followed by suitable diapause inducing and terminating protocols.