Assessment of Dispersal and Parasitism of the Laboratory Reared Trichogramma evanescens West. under Field Conditions

Abstract

Trials were conducted in a cotton field at Qaha Research Station, Qaluobia governorate, Egypt, to evaluate the dispersal ability and parasitism rate by the egg parasitoid Trichogramma evanescens West. (Hymenoptera: Trichogrammatidae), as well, to estimate the effect of parasitoid density from the releasing site on parasitism rate. Obtained data showed a limited dispersal ability for the parasitoid. The parasitism rates at 0, 50, 100, 150 and 200 cm. differed statistically from each other, being highest in the S. cerealella eggs placed at the shortest distance (43.03, 18.12, 10.92, 8.77 and 5.6%, respectively). The effect of releasing point and density on parasitism rate were also estimated. Increasing parasitoid density raised the rate of parasitism. When 2000, 3000 and 4000 parasitoids were released from the release point, the parasitism rates (mean percent ages for the whole 5 distances), were 33.21, 38.13 and 42.65%, respectively.