Functional response of Sunn pest egg parasitoid, Trissolcus vassilievi (Hym., Scelionidae) in response to thermal traits

The functional response of the egg parasitoid, Trissolcus vassilievi (Nees) (Hym., Scelionidae), on eggs of the sunn pest, Eurygaster integriceps Put. (Hem., Scutelleridae) was investigated at six constant temperatures (12, 15, 20, 25, 28 and 32 °C) for 8 hours. Using logistic regression, a type III functional response was determined for T. vassilievi at the two temperatures 15 and 32 °C. Any functional response was not detected at other temperatures. The Hassells’ type III model was used for estimating searching efficiency (a) and handling time (Th). At 32 °C the highest attack rateand the lowest handling time was recorded 0.2029 per hour and 0.1856 hour, respectively. Results show that the parasitoid can be used in the pest management programs at low and high temperatures.