Antixenosis Resistance of Different Poplar Clones to Three Important Pest in East Azarbaijan, Iran

East Azarbaijan province is one of the most important areas for poplar production and has the highest suitability of poplar plantation in Iran. Three species of poplar trees included Populus alba, P. nigra and P. x. euramericana are planted and usually attacked by different pests in this province. Melasoma populi L., Archips rosana (L.) and Pemphigus filaginis are some of important pests that cause direct and indirect damage on poplar trees. In this study were investigated antixenosis resistance of different poplar clones based on evaluation of pests accumulation on clones in natural condition. Based on the study results, clones included P. nigra Shabestar, P. alba Marand and P. nigra 62/154 respectivelly had more susceptibility and P. nigra Maragheh, P. alba Maragheh, P. alba Bostanabad and P. x. euramericana Bostanabad clones were the most resistant against M. populi. P. alba Mianeh clone was the most susceptible to A. rosana while, P. nigra Miandoab, P. nigra Maragheh and P. alba Maragheh had the highest resistance. About P. filaginis only P. alba Miandoab, P. nigra Marand and P. nigra Mianeh clones were infested to the pest and none of the other clones infested to the aphid.