The effect of photoperiod on development,reproduction and flight capability of armyworm (Mythimna separata) was examined under five different treatments of short photoperiod (LD8∶16),median photoperiod(LD 12∶12),long photoperiod(LD 16∶8),generally decreasing photoperiod(from LD 16∶8 to 12∶12)and gradually increasing photoperiod(from LD 8∶16 to 12∶12)at a constant temperature in laboratory.The results show that the length of development period of larvae experienced gradually decreasing photoperiods was one...