Neotropical Entomology 34(6): 945-949 (2005) Development and Thermal Requirements of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) on Eggs of Bonagota cranaodes (Meyrick) (Lepidoptera: Tortricidae)ABSTRACT -The aim of this study was to evaluate the development of Trichogramma pretiosum Riley on eggs of Bonagota cranaodes (Meyrick) under different temperatures. B. cranaodes eggs were maintained under seven constant temperatures (14, 18, 20, 22, 25, 28 and 30ºC), 70 ± 10% R.H. and, 14 h L. Forty replicates with 20 parasitized eggs each were kept in glass tubes (8.5 x 2.5 cm) covered with a plastic film. The method of hyperbole was used to calculate the temperature threshold (Tb) and the thermal constant (K). The Tb obtained was 11.9ºC and to thermal constant was 153,4 DD. The most favorable temperature range was from 25ºC to 30ºC, at which the shortest egg-adult development period and the highest survivorship were observed. (14, 18, 20, 22, 25, 28 e 30ºC), umidade de 70 ± 10% e fotoperíodo de 14h. Foram utilizadas 40 repetições com 20 ovos parasitados de B. cranaodes mantidos em tubos de vidro (8,5 x 2,5 cm), vedados com filme plástico transparentes. Para o cálculo do limiar inferior de temperatura (Tb) e da constante térmica (K) foi utilizado o método da hipérbole. A Tb foi de 11,9ºC e a constante térmica 153,4 GD. A faixa de temperatura mais adequada para a criação de T. pretiosum situou-se entre 25ºC e 30ºC, quando se obteve o menor ciclo ovo-adulto, maiores taxas de emergência e o maior número de indivíduos emergidos por ovo.