Effects of biological and environmental factors on the parasitism performance of Trichogramma evanescens Westwood, 1833 (Hymenoptera: Trichogrammatidae)

This study was conducted in 2024 at the Insect Rearing Laboratory of the Department of Plant Protection, Faculty of Agriculture, Tekirdağ Namık Kemal University, under controlled laboratory conditions to evaluate the effects of temperature, photoperiod, host density, female age and female density on the performance of Trichogramma evanescens Westwood, 1833 (Hymenoptera: Trichogrammatidae) using Ephestia kuehniella Zeller, 1879 (Lepidoptera: Pyralidae) eggs as host. The results indicated that temperature had a significant effect on parasitoid performance. The highest fecundity and female longevity were obtained at 25°C, whereas adult emergence declined at 30°C. Photoperiod also influenced parasitoid performance, and the highest parasitism level was recorded under the 16:8 (L:D) photoperiod. Continuous darkness resulted in a higher proportion of female offspring compared with other photoperiod conditions. Host density also affected parasitism performance, and higher parasitism levels were observed at host densities of 100 and 150 eggs. Female age and female density influenced parasitoid performance. The highest fecundity was observed in one-day-old females, whereas fecundity declined with increasing female age. In addition, parasitism per female decreased as female density increased, while higher female emergence rates were obtained at low female densities.