Effect of mating and previous parasitism on functional response of Trissolcus djadetshkoe Hym Scelionidae an egg parasitoid of Eurygaster integriceps Hem Scutelleridae
In order to select a suitable species of the trichogrammatid wasps for biological control of the codling moth, some of the trichogramatid wasps were collected and identified from the apple orchards located in north east of Tehran province by direct sampling on the codling moth eggs and using egg traps. Furthermore, laboratory experiments were carried out according to completely randomized design for evaluation of fecundity and longevity of the collected wasps at temperatures 22, 24, and 26degC by using the eggs of Sitotroga cerealla as factitous host. Moreover, host acceptance of the codling moth eggs by the wasps was examined statistically after five generation rearing on factitious host. Three species of the trichogrammatid wasps, Trichogramma brassicae, T. pintoi, and T. embryophagum, were collected and identified from the studied apple orchards located in Damavand and Rodehen region. According to the obtained results, fecundity of the evaluated wasps at temperatures 24 and 26degC were higher statistically than temperature 22degC. The highest values of the fecundity of T. pintoi and T. embryophagum were 30.96 and 26.46 eggs/female at studied time interval, respectively. In order to examine host acceptance level of the wasps, the percentage of the host eggs parasitism were determined as 73.64% and 17.70% by T. embryophagum and T. pintoi, respectively. Considering all the obtained results, collected native strain of T. embryophagum was introduced as a suitable choice for extension of the biological control program aginst the codling moth in apple orchards located in study region.