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 30°C), 70 ± 10% R.H. and, 14 h L. Forty replicates with 20 parasitized eggs each were kept in glass tubes (8.5 × 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 11.9°C and to thermal constant was 153,4 DD. The most favorable temperature range was from 25°C to 30°C, at which the shortest egg-adult development period and the highest survivorship were observed.