بررسي تغييرات جمعيت پارازيتوييدهاي شته هاي سورگوم جارويي در منطقه ي ميانه

Population fluctuation of broom corn aphid parasitoids in Miyaneh region, Iran

Aphids are the most injurious pests of broom corn in Miyaneh region, Iran. Chemicals are used in different times for plant protection by farmers, regardless to natural enemy activity. Identification of native natural enemies is essential in integrated pest management programs. In this research, broom corn aphid parasitoids were collected and identified and their population fluctuations were also studied in comparison to their aphid hosts. For this purpose, aphid colonies were sampled and mummies were collected. Live aphids were also reared on broom corn seedlings for 10 days to select parasitized aphids from unparasitized ones. Results revealed that, there were two aphid species in broom corn fields of Miyaneh region, including Schizaphis graminum and Rhopalosiphum maidis. Parasitoids were collected on both mentioned aphids and were belong to genus Aphelinus, family Aphelinidae. High parasitoid population was seen when aphid population was high, and vise versa. Significant positive correlation of aphid and parasitoid populations was duo to host specificity and might be a criterion of effective natural enemies.