花绒寄甲寄生松褐天牛的关键环境因子研究

为了明确林间影响花绒寄甲Dastarcus helophoroides(Fairmaire)寄生率的关键环境因子,本文在试验地不同位置设置诱木引诱松褐天牛Monochamus alternatus Hope成虫产卵,并在诱木上释放花绒寄甲成虫,之后调查诱木的生长环境及诱木上花绒寄甲的寄生率,并对各环境因子与花绒寄甲寄生率进行逐步回归分析,筛选出关键环境因子。结果表明,花绒寄甲寄生率(Y)与坡位(X₅)呈显著正相关关系,与主林层郁闭度(X₈)呈显著负相关关系,依此建立多元回归模型：Y＝0.4146＋0.5741X₅―0.4382X₈。经检验,平均差异程度为0.2209。因此,可试用该模型对花绒寄甲寄生率进行评估。以上研究为释放花绒寄甲防治松褐天牛提供参考。

Key Environmental Factors Affecting Parasitism of Monochamus alternatus Hope by Dastarcus helophoroides Fairmaire

Dastarcus helophoroides (Fairmaire) is an important parasitoid of Monochamus alternatus Hope in China, but shows varying parasitism depending on the microenvironment. The influence of key environmental factors on parasitism by D. helophoroides was investigated. Fifteen environmental factors of 65 plots were surveyed, and the data were related to parasitism rate by stepwise regression analysis. The results showed that there was a significant positive correlation between slope position and parasitism rate, and a significant negative correlation between crown density and parasitism rate. Using these two key factors, a multiple regression model was established for forecasting the parasitism by D. helophoroides. The average difference degree was detected to be 0.2209, which indicates the model is suitable for forecasting the parasitism rate. These studies provide a basis for releasing the parasitoid to control the longhorn beetles.