蜀柏毒蛾自然种群生命表研究初报

1990年～1991年在中江县柏木林区对蜀柏毒蛾自然种群生命在进行了系统观测,组建了3个生命表。蜀柏毒蛾自然种群生存曲线属Southwood N型,卵期和低龄幼虫期死亡率很高,主要消亡因子是卵寄生蜂、越冬卵不育、初孵幼虫的生理死亡及雨水的作用。1990、1991年第1代种群增长指数为0.9066。0.2063,下代种群均呈下降趋势,而1990年越冬代种群增长指数为12.1732,下代种群呈上升趋势。天敌的控制作用表现在中老龄幼虫以及蛹期,且随着虫龄的增大而越加显著。因此采取化学防治方法控制虫灾时,宜在低龄幼虫期进行。

A primary Report on Studies of Life Tables of Natural Parocneria orienta Populations

From 1990 to 1991, systematic observations were made on life tables of natural PnTcoueria art, enta populations in cypress forest areas in Zhongjiang County, Sichuan Province, and three life ta -bles were set up. Their life curves belong to Southwood IV. Their death rates in the periods of eggs and lower instar larvae are very high. The factors resulting in their death include hymenopterous parasites on eggs, sterility of wintering eggs, physiological death of primary larvae and rain. The growth indexes of the first generation populations in the years 1990 and 1991 are 0. 9066 and 0. 2063, but the next generation populations tend to drop. The growth index of the wintering gener ation populations in 1990 is 12. 1732, and the next generation populations have a tendency for increase. The control effect of natural enemies can be found in the periods of middle and old instar larvae and pupal stage, and becomes more and more considerable together with the increase of insect instar. As a result, it is suitable to use chemical methods to control insect pest in the period of lower instar larvae.