The present study was carried out to investigate the disruptive effects of methanolic, petroleum ether and n-butanol extracts of N. sativa seeds, at 30.0, 15.0, 7.5, 3.7 & 1.8%, on the oviposition efficiency and other parameters of reproductive capacity of S. gregaria. The average number of egg pods/female slightly or remarkably decreased, depending on the extract, concentration and time of treatment. The n-butanol extract was the most potent inhibitory one on the average number of eggs/pod. Treatment of penultimate or last instar nymphs with N. sativa resulted in remarkably or slightly regressed oviposition rate, depending on the extract and concentration. Various reducing effects of N. sativa extracts on fecundity were determined. However, the strongest reducing effect was exhibited at the higher two concentrations, irrespective of the extract. After treatment of penultimate instar nymphs, the most tremendously reduced fertility was recorded by n-butanol extract. After treatment of last instar nymphs, fertility was affected, significantly or insignificantly, depending on the extract and its concentration. Treatment of penultimate instar nymphs resulted in slightly prolonged incubation period by methanolic extract indicating a slow down embryonic rate. A similar inhibitory effect on this rate could be almost obtained by petroleum ether extract while the strongest inhibitory effect was exhibited by n-butanol extract, at the majority of its concentrations. After treatment of last instar nymphs, the petroleum ether extract pronouncedly affected embryonic developmental rate during a prolonged incubation period.