螟虫长距茧蜂搜索寄主利它素的应用研究

APPLICATION OF HOST-SEARCHING KAIROMONES IN MANAGEMENT OF MACROCENTRUS LINEARIS (NESS) (HYMENOPTERA: BRACONIDAE)

试验表明,螟虫长距茧蜂Macrocentrus linearis(Ness)雌蜂在利它素抽提物处理区域内的搜索时间明显较未处理的对照区长,雌蜂在处理区的搜索时间与利它素的浓度有一定的相关性,但并不完全随着(?)它素浓度的增高而增加。应用利它素能明显地缩短雌蜂找到寄土的时间,然而当使用的利它素浓度过高时,则显示相反效果。寄主密度高低对利它素的应用效果产生明显影响。室外笼罩试验证实,在玉米植株上全面喷洒利它素能明显地提高所释放的螟虫长距茧蜂对亚州玉米螟Ostrinta furnacalis(Guenee)幼虫的寄生率,利它素处理区的玉米螟幼虫寄生率比对照区高13～18％。

The results of experiments performed in the laboratory showed that the host-searching time of the female Macrocentrus linearis in the area treated with an extract of the frass of its host Ostrinia furnacalis was apparently longer than that in the untreated area, though it did not increase proportionally with the amount of the kairomones. It was also found that the use of kairomones could decrease the host-finding time of M. linearis, but when the amount of kairomones was applied in excess, the difference of host-finding time between treatment and control disappeared. Host density had an important influence upon the efficiency of the kairomones.The results of experiments in the outdoor cages indicated that spraying the extract from host frass on corn plants resulted in an increase in parasitization of M. linearis on the corn borer. The rate of parasitization was increased 13-18% on the sprayed corns as compared with the untreated corns.