Pathogenicity Research on Streptococcs sp. to Saperda populnea Study on Saperda populnea Harming Populus × xiaozhuarica cv. ‘Baicheng‘ Relationship between Secondary metabolites of Poplar and Enzymatic Activity of Saperda populnea STUDIES ON ESTABLISHING LIFE TABLES OF PESTS SAMPLING IN DIFFERENT FOREST LAND WHERE THE PESTS EMERGED IN DIFFERENT TIMES IN THE SAME ENVIRONMENT Scanning Electron Microscopic Observations of Sensilla on the Antennae of Saperda populnea and S. balsamifera