缘腹茧蜂对草地贪夜蛾的寄生能力及子代发育情况研究

Parasitic Efficacy and Development Performance of Cotesia marginiventris(Cresson)on Spodoptera frugiperda(Smith)

室内对比研究了缘腹茧蜂(Cotesia marginiventris)对草地贪夜蛾(Spodoptera frugiperda)及粉纹夜蛾(Trichoplusia ni)的寄生情况,同时研究了玉米和人工饲料喂养草地贪夜蛾时缘腹茧蜂的寄生情况以及缘腹茧蜂结茧及羽化的生物学特点,旨在为草地贪夜蛾生物防治提供参考。结果表明,每日20头幼虫条件下,单头缘腹茧蜂对草地贪夜蛾2龄幼虫的寄生率可达98.50%,子代可发育寄生蜂176.0头,其茧—成虫存活率为85.9%,与以粉纹夜蛾为寄主时差异不显著;卵—茧(7.74 d)、茧—成虫(5.53 d)发育历期,茧质量(2.38 mg),茧长宽(2.61、0.95 mm)均显著低于以粉纹夜蛾为寄主时;处女雌虫和处女雄虫寿命分别为10.87 d和9.70 d,显著高于以粉纹夜蛾为寄主时。缘腹茧蜂寄生以人工饲料饲养的草地贪夜蛾时,其卵—茧发育历期、茧长宽和茧质量均显著高于寄生以玉米饲养的草地贪夜蛾时,而寄生率、子代茧—成虫存活率、处女雌雄虫寿命无显著差异。以人工饲料饲养的草地贪夜蛾为寄主时,缘腹茧蜂体外结茧高峰在16:00—18:00。茧的羽化高峰雌雄有所差异,雌虫羽化高峰在20:30至次日1:30,雄虫羽化高峰为8:30至12:30。综上,缘腹茧蜂对草地贪夜蛾的寄生能力较强,以人工饲料饲养的草地贪夜蛾繁殖缘腹茧蜂潜力较大,可以利用缘腹茧蜂对草地贪夜蛾进行生物防治。

The parasitic efficacy and development performance of Cotesia marginiventris(Cresson)on Spodoptera frugiperda(Smith)and Trichoplusia ni were studied,as well as parasitic efficacy and development performance on S.frugiperda fed with host plant of corn or diet were compared,and rhythms of cocoon and emergence of the parasitoid were investigated.Results showed that the parasitic ratio of C.marginiventris on S.frugiperda was 98.50%when provided with 20 larvae of S.frugiperda every day during the whole life.For offspring,176.0 parasitoids successfully developed,and the survivorship from cocoon to adult was 85.9%,which were not significantly different with those on T.ni.The development duration from egg to cocoon(7.74 d)and cocoon to adult(5.53 d),the cocoon weight(2.38 mg),the cocoon length(2.61 mm)and width(0.95 mm)were significantly lower than those on T ni.However,the longevities of virgin female and male were 10.87 d and 9.70 d respectively,which were significantly higher than those on T.ni.When parasitizing on S.frugiperda fed with corn compared with diet,the development duration of C.marginiventris from egg to cocoon was shorter,the size of cocoon was smaller and the weight was lighter,while the parasitic ratio,survivorship from cocoon to adult,longevity of virgin female and male were not significantly different.When parasitizing on S.frugiperda fed with diet,cocooning peak of C.marginiventris was mainly from 16:00 to 18:00,while emergence rhythm of female and male was different,the peak was from 20:30 to 1:30 the next day for female and from 8:30 to 12:30 for male.The results indicate the parasitic efficacy of C.marginiventris on S.frugiperda is high,S.frugiperda reared with artificial diet has great potential to propagate C.marginiventris,and it can be used for biological control.