Distribution of Monochamus alternatus larvae on dead standing trees of Pinus massoniana

To clarify the distribution pattern of Monochamus alternatus larvae on dead standing trees and provide guidance for local pest surveys and scientific control, we dissected dead standing Pinus massoniana trees in the Qingshanling Forest Area of Fushun County and systematically counted the number of M. alternatus larvae at different trunk heights and diameter at breast height (DBH) classes. The results showed that: (1) M. alternatus larvae had an aggregated distribution on P. massoniana trunks, with the aggregation degree increasing with the rise of population density; (2) The number of larvae increased first and then decreased with the increase of trunk height, mainly concentrating at 5-9 m of the trunk, and the larval number peaked at the 7-8 m segment; (3) The number of larvae was significantly positively correlated with DBH, and the number of larvae in xylem was significantly higher than that in phloem; (4) There was an extremely significant linear relationship between the total number of M. alternatus larvae on the whole P. massoniana tree and the larval number at the 2-3 m trunk segment, as well as DBH.