Study on the Main Occurrence Regularity of Pimelocerus perforates,A Major Pest of Ash Trees Fraxinus spp.
The basic biological and ecological characteristics of the destructive stem-boring pest Pimelocerus perforatus of ash trees were described in Shanghe county,including life history,occurrence and damage characteristics.The insect had 1～2 generations a year in Shanghe county,and overwinter as adults in the ground soil around the base of ash tree trunk and 3rd to 7th instar larvae in the areas where the tree trunk base and infested root neck from October to November.Adults and larvae of P.perforatus can be found throughout the entire growth period of the ash tree.The overwintering adults were first discovered in late March,and most adults began to appear in early April.The adult of P.perforatus has a long longevity,with most surviving for 100～400 days and some individuals exceeding 600～800 days.There are three peak periods for adult of P.perforatus throughout the year,including the concentration period of overwintering adults in early to mid or mid to late April,the concentration period of overwintering new adult from mid to late June to early-July,and the concentration period of the first generations adults from mid to late August to mid-September.The adult of P.perforatus has the habit of climbing up and down trees,death-feigning,and certain phototaxis,with an average female ratio of 0.47.The adult of P.perforatus prefer the environments with dark and humid,and are not resistant to high temperatures and dryness.The adult of P.perforatus can mate dozens of times over their lifetime.A female adult can lay eggs for 42 day-times and 88 eggs within 62 days,with an average egg duration of 7.9 days(6.2～11.5)at temperature of 29℃.The eggs of P.perforatus are laid in the bark layer at the root neck,crevices or wounds on the surface of the ash trunk base,and are covered or partially covered with fecal debris.Preliminary determination result showed that the larvae have 7 instars.1～4th instar larvae damage the bark and shallow layers of the phloem and xylem,while 5～7th instar larvae damage the xylem and form tunnels.Clarifying the basic biological and ecological characteristics of P.perforatus is of great significance for prediction,forecasting,and comprehensive control.
万方数据
维普
