赤眼蜂防治小菜蛾问题

赤眼蜂Ｔｒｉｃｈｏｇｒａｍｍａ（Ｔ．ｃｏｎｆｕｓｕｍＶｉｇｇｉａｎｉ，＝Ｔ．ｃｈａｌｏｎｉｓ，Ｎａｇａｒａｊａ，ｎｅｃ．Ｉｓｈｕ）于卵期降低小菜蛾Ｐｌｕｔｅｌｌａｘｙｌｏｓｔｅｌｌａ（Ｌ．）种群密度，但对其幼虫期的天敌不会随即受到影响，相对地提高了天敌的作用。本文在生命表的基础上应用于扰作用控制抬数评价这两者的相辅相成的效果。试验分析结果表明，赤眼蜂对小菜蛾种群动态的控制作用是比较明显的。小菜蛾的产卵高峰期比较长，卵的发育历期比较短，这是应用赤眼蜂的不利条件．赤眼蜂成虫散放后继续扩散，同时不可避免逐日死亡，这也不利于寄生率的提高。本文通过对赤眼蜂成虫扩散行为的观察，结合小菜蛾的上述特点，讨论提高赤眼蜂对小菜蛾防治效果的措施。

Studies of the Effectiveness of Trichogramma on Diamondback Moth

The population size of diamondback moth Plutell xylostella (L.) (DBM)would decreasedftom egg stage by releasing Trichogramma(T.confusum Viggiani=T.chilonis,Nagaraja,nec.Ishu),but the populations of natural enemies of the larvae should not decreeed immediately.Inthis case,the effects of the natural enemies would increasetl relatively.In this parper,based onthe life table method,by means of the interference indices of population control(UPC),the com-plemenfw effects of each other were studied.The results and analysis showed that the percentageof parasitic eggs was only 32.9%,but the UPC was in 0.24.It gave a gfor resuIt in the popula-tive dyna1nics control.According to the resuIt of the experimenis of selective behaviol1r on the de-velopment stage of egg and the behav1o1ir of the expansion of adults after releasing,the methodsof releasing Trichogramma were suggested. It u1ay be helpful to improve the effectiveness of Trichogr-amma to control DBM.