Occurrence regularity of Monochamus alternatus in Chongqing

M.alternatus occurred one generation a year in Chongqing and overwintered mainly as 3-4 instar larvae in the tunnel in xylem.The adult emerged in late April.In the first ten days of November,the larva began to overwinter.The emergence date of adults was different because of different altitudes and special environment.Rosin embedding and parasitism were the main reasons for unhatched eggs.Top mortality(48.6%) of larvae occurred before they fed xylem.In xylem,the risk of being preyed was quite low.Trend index of population I=18 239.13/1 214=15.02.The study provided some theoretical instruction on the control of M.alternatus and the epidemic of B.xylophilus in southwest of China.