Abstract: The developmental duration, survival rates and fecundity of tobacco budworm Helicoverpa assulta (Guen6e) were studied in the laboratory. The results showed that the survival rates of whole generation were 23.28, 37.04, 44. 22, 30.21, and 8.28%, and the trend indexes of population were 13.45, 65.68, 72. 57, 30.69, and 0,at the constant temperatures of 20,24, 28,32, and 36℃, respectively. The development threshold temperatures for eggs, first, second, third, fourth, fifth, and sixth instar larvae, prepupae, and pupae were 12.03℃, 10.39℃, 8.97℃, 8.96℃, 10.87℃, 11.23℃, 9.16℃, 11.40℃, and 10.69℃, respectively. Their effective accumulated temperatures were 47.62, 56.46, 44.30, 40.57, 26.26, 33.94, 64.61, 34.50, and 202.45 day-degrees, respectively. Higher temperatures exposed daily for a short time,above 39℃ for 4 h/day, were unfavorable conditions for the living of this insect. At 28° and 32℃, humidity condition could influence the survival of the first stadium larvae, prepupae and pupae, but had no significant effect on the developmental duration.

Key words: Helicoverpa assulta (Guen6e), temperature, humidity, population