A Study of the Relationship between Population Fluctuations of Sunn Pest Eurygaster integriceps and Environmental Factors in East Azarbaijan Province

Sunn pest is considered as the most important insect pest of wheat and barley in Iran. Different studies have shown that various biotic and abiotic factors affect sunn pest populations. These factors can influence the population density of the pest which in turn can play a role in the control of the pest. In this study the relationship between sunn pest population fluctuations and climatic conditions, the area under wheat and barley cultivation as well as the area under chemical control was investigated. In addition, the possible influence of overwintering adults’ weight and environmental factors on sunn pest mortality in the overwintering sites was studied. Field data were collected from six infested counties of East Azarbaijan province, including Tabriz, Bostanabad, Sarab, Mianeh, Heris and Hashtrood during three study years. From the variables under study, only mean weights of the overwintering insects, altitude, mean monthly minimum relative humidity, as well as rainfall during the months of December, January, February and March indicated significant relationships with sunn pest mortality in the overwintering sites. The relationship between the area under wheat and barley cultivation and sunn pest population changes was not significant but there was a close relationship observed between the area under chemical control and sunn pest population fluctuations. Similar studies in other regions with long history of sunn pest outbreaks will produce valuable information that can be helpful in predicting sunn pest outbreaks.