Abstract
Experiments were conducted to ascertain the factors regulating larval diapause of the rice stem borer, Chilo suppressalis. The results clearly showed that juvenile hormone secreted from the corpora allata was a key factor, which not only induced but also maintained the larval diapause of this borer. A notable fact was that the diapause was definitely induced by application of juvenile hormone, even under a long day photoperiod and where normally diapause was terminated by chilling at 5°C for 40 days. Further, it was concluded that the induction of diapause was closely related to the high juvenile hormone titer during the early stage of the last larval instar.
