稻螟赤眼蜂与二种赤眼蜂对水稻二化螟卵寄生竞争作用

Interspecific interference of Trichogramma japonicum with other two Trichogramma species on eggs of the rice stripped stem borer, Chilo suppressalis(Walker)

稻螟赤眼蜂是我国水稻二化螟的优势卵寄生蜂,本文在室内条件下,初步研究了稻螟赤眼蜂分别与松毛虫赤眼蜂和螟黄赤眼蜂在水稻二化螟卵上的种间竞争作用。结果表明,同时接入稻螟赤眼蜂和松毛虫赤眼蜂时,寄生水稻二化螟卵(40.2粒)及子代雌蜂总数(32.0头)最多,且松毛虫赤眼蜂平均寄生二化螟卵的数量(26.5粒)明显高于单独接蜂的平均寄生的数量,后代雌蜂比率(76.3%)明显低于单独接蜂时的雌蜂比率,发育历期(10.7 d)明显长于接入同种时的发育历期。而稻螟赤眼蜂和螟黄赤眼蜂共存时,螟黄赤眼蜂平均寄生二化螟卵的数量(10.3粒)、后代雌蜂比率(75.3%)以及发育历期(8.0 d)与单独接蜂时相似;同样,当稻螟赤眼蜂与松毛虫赤眼蜂混合接蜂时,稻螟赤眼蜂平均寄生二化螟卵的数量(14.4粒)、后代雌蜂比率(79.0%)以及发育历期(8.6 d)与单独接蜂时相似,但是,当稻螟赤眼蜂与螟黄赤眼蜂混合接蜂时,其后代雌蜂比率(76.7%)明显低于单独接蜂处理,而发育历期(8.8 d)明显长于单独接蜂处理。总的来看,在二化螟卵上,同时接入二种赤眼蜂时,蜂种间存在一定的竞争作用,其中混合接入稻螟赤眼蜂和松毛虫赤眼蜂时,对水稻二化螟的控制效果最佳。

Trichogramma japonicum Ashmead is a dominant egg parasitoid species against the rice stripped stem borer,Chilo suppressalis（ Walker） in China. The interspecific interference of T. japonicum with Trichogramma dendrolimi Matsumurg and Trichogramma chilonis Ishii on C. suppressalis eggs was preliminarily determined in the laboratory. The results showed that both of T. japonicum and T. dendrolimi releasing together parasitized the largest number of host eggs（ 40. 2）,and had the highest number of female offsprings（ 32. 0）. When T. japonicum and T. dendrolimi were released simultaneously,T. dendrolimi female parasitized significantly more host eggs（ 26. 5）,had lower percentage of female progeny（ 76. 3%）and longer developmental time（ 10. 7 d）,compared to two T. dendrolimi females released together. When T. japonicum and T. chilonis were released simultaneously,however,T. chilonis parasitized similar number of host eggs（ 10. 3）,and had similar percentage of female progeny（ 75. 3%） and developmental time（ 8. 0 d） to two T. chilonis females released together. Similarly,when T. japonicum and T. dendrolimi were released simultaneously,T. japonicum parasitized similar number of host eggs（ 14. 4）,and had similar percentage of female progeny（ 79. 0%） and developmental time（ 8. 6 d） to two T. japonicum females released together. When T. japonicum and T. chilonis were released simultaneously,T. japonicum had lower percentage of female progeny（ 76. 7%） and longer developmental time（ 8. 8 d）,compared to two T.japonicum females released together. The results indicated that interspecific competition occurred when two Trichogramma species were simultaneously introduced to parasitize C. suppressalis eggs. Generally,simultaneously releasing T. dendrolimi and T. japonicum exhibited the best biocontrol effectiveness on the rice stripped stem borers.