Investigating of Diversity and Species Richness of the Wheat Aphids and Introducing their Coccinellid Predators in Urmia, West-Azerbaijan Province

West Azerbaijan Province is a mountainous area in the North West of Iran that has a high potential for the production of grains/cereals. The diversity of active aphids species and their coccinellids predators in wheat farms of this province was studied for two years during 2010 and 2011. The present study identified six harmful species of aphids and five species of ladybird beetles being their main enemies at different wheat growth stages and different sampling dates. In 2010, Schizaphis graminun (Rondanii) species was the most frequently found species and was considered as dominant species in the area. The highest species richness of the collected grains/cereals aphids was recorded five species in the early of May in 2010. The highest degree of Shannon diversity index (1.81) was also related to 2nd of May, 2010 and the least amount of the same index (0.65) was found in 1st of July in the same year. In 2011, Metopolophium dirhodum (Walker) species had the most frequency rate and was regarded as the dominant species. The highest species richness of the collected aphids of the grains was observed during the mid-June in 2011. The highest degree of Shannon diversity index (1.25) was related to 15th of April 2011 and the least amount of the same index (0.81) was found in 11th of March in that year.