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小菜蛾Plutella xylostella, DBM 是十字花科的重要害虫。本文应用昆虫病原线虫斯氏线虫的六个种和异小杆线虫的一个种对小菜蛾四龄幼虫进行室内测定,筛选出斯氏线虫Steinernem a carpocapsae A24 和异小杆线虫Heterorhabditisbacteriophora 8406 为防治小菜蛾的较理想线虫种,田间小区试验也证实了这点。根据昆虫病原线虫在叶面上需有水膜才可移动及寻找、进攻寄主的特性,若施线虫的当天阳光强烈,则选择日落后的下午6 时左右施用线虫,并且先浇一遍水后再施用线虫,线虫寄生死亡率可提高33.9% ;在偏弱的阳光下的下午4 时左右施用线虫,添加0.1% 高酯膜可提高寄生死亡率9.5% ,但在较强的阳光下施用线虫,则两者的效果相似,且寄生死亡率在20% 以下。室内试验表明,斯氏线虫S.carpocapsaeA24 和异小杆线虫H .bacteriophora 8406 对小菜蛾的蛹、成虫也有感染作用。实践证明,应用昆虫病原线虫防治小菜蛾可起到一定的控制作用;若与其它生物因子配合使用,可望获得更好的效果,以便推广应用。
Plutella xylostella, DBM is an important pest of Cruciferae. In this paper, four species of Helminthomonas nematode and four species of Helminthosporidium spp. Were used for indoor determination of the fourth-instar larvae of Plutella xylostella. Steinernem carpocapsae A24 and Heterorhabditis bacteriophora 8406 were screened for the control of Plutella xylostella The more ideal species of nematodes, field experiments also confirmed this. According to the entomopathogenic nematodes need water film on the foliage to move and look for, to attack the characteristics of the host, if the day of nematode strong sunlight, then choose to use the nematode around 6 pm after sunset and pour water again before Nematode and nematode parasitic mortality increased by 33.9%. In the weak sunlight, nematodes were applied at around 4:00 pm. The addition of 0.1% high ester film increased the parasitic mortality by 9.5% The effects of both are similar and the parasitic mortality is below 20%. Laboratory tests showed that S.carpocapsaeA24 and H. bacteriophora 8406 also infected chrysalises and adults in the diamondback moth. Practice has proved that the application of entomopathogenic nematode control diamondback moth can play a role in control; if used in conjunction with other biological factors, is expected to get better results in order to promote the use of.