In this study, experiments were performed to investigate the effect of the exposure of pupal stage (24 h old) of Pectinophora gossypiella and Earias insulana to power supply magnetic flux (MF) of level 180mlli- tesla for different times (2, 6 and 12 minutes) and its latent effect on  emerged adults. Results showed that a direct effect on exposed pupae caused a percent of pupal mortality in bothinsects that increased by the increase of exposure time. Data recorded a significant elongation in the pupal duration of both insects, as a result of magnetic exposure with more efficiency for 12min. exposure followed 6min. exposure and no observed effect for 2min. exposure. Data also indicated a high reduction in the percent of emerged adults resulted from magnetized pupae in contrast the percent of adult malformed was highly increased in comparison with control.  The reduction in adult emergence and malformed percent was increased by the increase of exposure time in case of P. gossypiella treatment while, the process is reversed for E. insulana.   A high reduction in numbers of eggs laid by females resulted from (12 and 6min.) MFs exposure was also reported differs to the slight effect of (2min.) MFs exposure for both  P. gossypiella and E. insulana,  in comparison with control. In addition a high reduction in egg hatchability percentages was also recorded with more efficiency on E. insulana especiallyin12 min. MFs exposure compared to control.