两年一代落叶松毛虫的预测预报技术及防治指标的研究

Study on the Forecast Technique and Control Index of Larch Caterpillar of A Cycle in Two Years

１９９３～１９９５年在牙克石林区研究了两年一代落叶松毛虫的发生期与物候和二十四节气的相关性；发生量与５月份温雨系数和幼虫越冬后排粪量的相关性；建立了以温雨系数ｘ１、排粪量ｘ２为自变量，发生量为因变量ｙ的回归估测模型：ｙ∧＝１９６．２６８０－２３．５１７０ｘ１，ｙ∧小虫＝２．４４９９＋０．０７３２ｘ２，ｙ∧大虫＝１１．９７００＋０．０２７８ｘ２，兴安落叶松的失叶量超过４５％，对其高、胸径及材积生长有显著影响。在５月中旬前，当有虫株率超过４０％，大虫虫口密度超过５０头／株，小虫虫口密度超过１０１头／株时，必须防治。

This article deals with the correlation among the occurrence period of Dendrolimus superans (Butler),phenology and 24 solar terms as well as its occurrence amount,warm rain coefficient in May and overwintering larva′s shit in Yakeshi forest destrict from 1993 to 1995. We set up the regressive estimate model of the volume of occurrence (y):y∧ =196.268 0-23.517 0 x 1,y ∧(larva)=2.449 9+0.073 2 x 2,y ∧(adult)=11.970 0+0.027 8 x 2 ,in which the warm rain coefficient and larva′s shit act as dependent variable. The reasearch proves that it makes a great differencc to the height,the chest diameter and the volume of tree when loss amounts of Larix gmelinii leaves go beyond 45 percent in the total. Before the middle of May,the numbers of the trees which have insects is over 40 percent of the total trees,and the mature larvae adult insect density in each tree is over 50 heads and the young larvae density is over 101 heads,control measure should be adopted.