Abstract: Effects of water intake on diapause termination and pupation of overwintered larvae of Asian corn borer (ACB) were determined by providing the larvae with water on the 5th, 15th, 25th, 35th, 45th and 55th day after incubation at the alternative temperatures from 22℃ to 28 ℃(22～28℃) and 16℃ to 22℃(16～22℃), respectively. The results showed that the larvae were incapable of terminating diapause and completing prepupal development until they had drank water. The survival and pupation rates of the larvae increased with increase of larval weight because of water drinking. The highest pupation rate at 22～28℃ was recorded when the larvae drank water on the 35th day while that at 16～22℃ occurred when the larvae drank on the 55th day. The diapause development of the larvae was more rapid under 22～28℃than under 16～22℃ whenever water was offered. Therefore, it is concluded that the raining time and precipitation in spring may affect the pupation progress and rate of development of the overwintered ACB larvae in field.

Key words: Ostrinia furnacalis, terminating diapause, drinking water, alternated temperature