松突圆蚧危害程度划分的研究

PRELIMINARY STUDY ON CLASSIFICATION ABOUT DAMAGE DEGREE OF HEMIBERLESIA PITYSOPHILA TO MASSON PINE FORESTS

松突圆蚧(Hemiberlesia pitysophila Takagi)是近几年发现危害马尾松林成灾性害虫,其危害情况已有了一些报道。松突圆蚧危害程度的划分目前尚无统一的标准,有的用松针上的虫口密度,有的采用危害症状划分,但无具体的划分指标。为此,笔者自1988年起,用表征划分法对松林的被害程度进行了分类,并用解析木的生长材料进行了校验。

A classification standard about the damage degree of a new pest Hemiberlesia pitysopkila Takagi to masson pine (Pinus massoniana) forests had been put forward in this paper based on damage characteristics of the pine needles and twigs. The standard included 4 grades:(1)light: more than 80 % needles on 2-year-old twigs are green and yellow needles are seldom;(2)middle: about 50 %~80% needles on 2-year-old twigs are green and the others are wilt, the twigs slightly bend and wilt;(3)serious: about 50 %~80% needles on 2-year-old twigs are wilt, some fall and the twigs wilt obviously;(4)very serious: over 80 % needles on 2-year-old twigs are wilt and fall, the twigs wilt severely, some trees appear dying.Through the analysis of comparison between the field classification using the standard above and the differences of volume growth rate of 60 stem analysis, it has been proved that the classification standard has a high accuracy up to 87.73% and it could be used for the pest control.