沙棘木蠹蛾危害特性与种群数量的时空动态研究

作者于2003年5月至11月对沙棘木蠹蛾卵和幼虫的危害特性和种群数量的时空动态进行了研究.结果表明:沙棘木蠹蛾主要产卵在干部树皮裂缝、伤口等处，卵孵化后，初孵幼虫首先取食树干的韧皮部，然后逐渐向下转移危害根部.根部幼虫主要取食木质部，形成多条纵向的蛀道，通过蛀道在主根与侧根、侧根与侧根间进行转移危害.树干上的卵和初孵幼虫多集中在2 m以下，而根部的幼虫主要聚集在距离地面20 cm以内的主根上.从5月至11月，非当年生幼虫基本呈现递减的变化趋势，6月和10月减少的幅度较大.当年生幼虫则从7月逐渐增加至9月达到最大，而后又急剧减少.从8月到11月，幼虫的聚集位置和种群数量都呈现向树下部转移的趋势，10月初转移至根部的幼虫达70.5％，树干上分布的仅有29.5％，且大部分都集中在树干1.2 m以下的位置.11月初，幼虫已基本转移至地下根部，此时树干上幼虫分布很少. 

Harm characteristics and population dynamics of Holcocerus hippophaecolus

The harm characteristics and population dynamics of Holcocerus hippophaecolus eggs and larvae were investigated from May to November, 2003 in Jianping County, northeast China. The eggs of seabuckthorn carpenterworm are largely distributed in the crevices and wounds of the stem of host trees. The newly-hatched larvae first harm the phloem of the stem and then transfers from the stem to the root. The larvae under the ground mainly damage the xylem and transfers between the taproots and the lateral roots. The eggs and larvae mostly aggregate below the 2 m height of the stem and the larvae in the roots aggregate within 20 cm of taproots under ground. From May to November, the larvae hatched in past years descended, especially in June and October. Then the larvae hatched in the new-year increased gradually from July and culminated in September, but decreased sharply later. From August to November, both aggregation location and population quantity of the larvae transferred from the stem to the root. In early October, 70.5% of larvae distributed in the root, and only about 29.5% in the stem, mainly aggregating below 1.2 m of the stem. In November, almost all larvae stayed in the root, seldom in the stem.