تغییرات جمعیت سن گندم، Eurygaster integriceps (Hemiptera: Scutelleridae) در مزارع گندم و جو و معرفی پارازیتوئیدهای مهم آن در پناهگاه‌های تابستانه و زمستانه در مناطق ورامین و شهرری

Population flactuations of the sunn pest, Eurygaster integriceps Putton was studied in the wheat and barley fields of five regions of Shahre Rey including, Esmail Abad, Shahed University, Dorsun Abad, Ghaleh Nou and Nazar Abad from 25th March 2009 to 10th June of 2009. Additionally important parasitoids of the sunn pest were collected and identified in different regions of Varamin and Shahre Rey. Upon the results of this research, appearance date and maximum population density of the sunn pest in Esmail Abad was in 25th March and 15th April, respectively Also the appearance of 1st to 5th nymphal instars were observed in 15th, 23rd April (both 2nd and 3rd nymphal instars), 5th May (both 4th and 5th nymphal instars), respectively. The first individual of the sunn pest and its maximum population density in the wheat fields around Shahed University was sampled in 1st April and 16th May, respectively, and the 1st to 5th nymphal instars were appeared in 15th, 23rd April (both 2nd and 3rd nymphal instars), 30th April and 5th May, respectively. In Dorsun Abad, the sunn pest and 1st to 5th nymphal instars appeared in the wheat fields in 25th March, 15th, 23rd, 30th April (both 4th and 5th nymphal instars), and 5th May, respectively, and the maximum population density of the sunn pest was obtained in 30th April. The appearance date and maximum population density in Ghaleh Nou was observed in 25th March and 23rd April, and for 1st to 5th nymphal instars were obtained 23rd, 30th April (both 2nd and 3rd nymphal instars) and 5th May (both 4th and 5th nymphal instars), respectively. The results of sampling in Nazar Abad indicated that appearance date and maximum population density of E. integriceps were 8th and 15th April, respectively Also the appearance date of 1st to 5th nymphal instars were determined in 15th, 23rd, 30th April and 5th May (both 4th and 5th nymphal instars), respectively. Regarding to the parasitoids of the sunn pests in Varamin and Shahre Rey, totally eight species including, Telenomus chloropus (Thomson), Trissolcus basalis (Wollaston), Trissolcus festivae (Viktorov), Trissolcus grandis (Thomson), Trissolcus rufiventris (Mayr), Trissolcus semistriatus (Nees), Trissolcus simoni (Mayr) and Trissolcus vassilievi (Mayr) were collected and identified from the fruit and forest tress, weeds and many crop fields around the wheat and barley fields.