【摘要】 <正> 对马尾松毛虫的防治,因越冬代的生长比较整齐,抗药性较差,此时进行防治,效果最佳。为了更好地做好防治工作,必须事先做好虫情的调查。但如何调查越冬代松毛虫的虫情,目前尚无统一的、既简便又准确的方法。有些文献提出在越冬前进行虫情调查,然后根据越冬期间的死亡率(一般认为是25％)预测越冬后的虫情。但由于越冬前松毛虫都在树冠上,调查时非常困难。张旭等用松毛虫落粪与其虫口密度的关系研究越冬代史情的调查方法,目前尚未推广应用。鉴于马尾松毛虫发生2～3代地区,其幼虫多以3～4龄在树皮裂缝中越冬的实际情况,杨仕海提出以2m树干上调查的数据乘以1.42来预测虫情。此方法更多还原

【Abstract】 During the winters of 1987 and 1988, 29 sample sites of Pinus massoniana were selected in Susong County and Qianshan County of Anhui Province, and population densities of Dendrolimus punctatus were investigated according to a designed method. Through the analysis of the data, we obtained the following results:(1) The caterpillars thoroughly enter into the state of overwintering at the end of December.(2) In young trees, nearly all the caterpillars overwinter in the clumps of the needles; in higher trees, nearly ail the caterpillars go down to the crevices of the bark to overwinter, and most of them conceatrate on the lower-parts of the trunks under 2 m. The percent cf the number investigated from the lower-parts of the trunks under 2 m to the number from the whole tree (p) is related to the population density of the sample sites (g), the regression model is p = 97.76-3.67 q .(3) The average value of the numbers investigated from the lower-parts of the trunks under 2m (u) can be used to estimate the population density of the sample sites (u):更多还原