The intensity of diapause of field-collected diapausing larvae of Olilo partellus (Swinhoe) and Chilo orichalcociliellus Strand (Lepidoptera: Pyralidae) was compared in the laboratory at 28 ± 0.5°C under a photoperiod of 12:12 (L:D)h. Chilo partellus terminated diapause faster than C. orichalcociliellus. Mean time to diapause termination was 9.7 days for C. partellus and 14.4 days for C. orichalcociliellus. Male and female C. partellus larvae terminated diapause and adults emerged at the same time, while significant differences were found in diapause termination and in emergence times between male and female C. orichalcociliellus.
