Identification of Syrphid Flies in Wheat Fields and Survey of Population Fluctuations of Dominant Species in Kurdistan Province

Syrphids are one of the most important natural enemies of wheat aphids. Larvae feed in aphid colonies and reduce the population. To identify these predators and their population fluctuation during wheat growing season، five fields with area about one ha were selected. Syrphids were swept weekly by standard insect net in the selected fields. The result showed that 14 species of flower flies occur in the wheat field of Kurdistan province which among them Eupeodes corollae with %52. 41of total population in 2002 and %47. 65 in 2003 has the highest frequency. Among predator species، Eupeodes nuba، Sphaerophoria scripta، S. turkmenicaand Eupeodes corollae constitute the largest part of syrphid population. Seven species of aphids were identified and their population changes were measured by weekly random sampling of 40 plants. Sitibion avenae and Schizaphis graminum were dominant aphid species where their frequency were measured as %66 and %30of total specimens in 2001 and %69. 5 and %25 of total specimens in 2002 respectively. The positive correlation between aphid population increase and emergence of syrphid larvae was discussed briefly.