不同径阶杨树杨扇舟蛾防治指标研究

经过对速生丰产林4-22cm径阶杨树蓄叶量、叶面积、杨扇舟蛾食叶量、人工模拟摘叶对杨树生长量的影响等因子的调查分析，得出胸径D与杨树单株叶面积S之间的回归关系式为S=1．491D^1.2681(相关系数r=0．975)，失叶强度与杨树材积年增长量的回归模型为V=0．0038—0．0028x-0．0004x^2(相关系数r=0．9865)，确定杨树的经济允许受害水平为失叶40％，杨树失叶强度的经济阈值为0．184，根据D、S的关系式，得出杨扇舟蛾幼虫理论防治指标E与胸径D的关系式为E九=28．5104D^1．2681，E阈=17．4864D^1．2681，根据E、D关系式，计算出不同径阶杨树杨扇舟蛾幼虫虫口密度的防治指标，结合各径阶杨树树冠投影中杨扇舟蛾幼虫折算系数及生命表推算出杨扇舟蛾1～4代幼虫达到防治指标时所对应的单位树冠投影中越冬蛹的防治指标。

Control indexes of Clostera anachoreta in poplars of different diameter grades

The analysis of the factors such as the amount of leaves,leaf area,defoliating amount of Clostera anachoreta and the effect of artificial removal of leaves on the poplar growth and so on of poplars with diameter grades from 4 to 22 cm in the rapid growing and high yield lands showed that the regression equation of breast height diameter(D) and leaf area per poplar(S) was S=1.491D;The regression model of defoliation intensity and the annual timber volume increment was V=0.003 8-0.002 8x-0.000 4x~2.So the economic threshold of damage was 40% defoliation and that of defoliation intensity was 0.184.The control indexes of population density of Clostera anachoreta larvae and the overwintering pupae of poplars with different diameter grades were calculated.