甘蓝夜蛾赤眼蜂对几种重要农业害虫寄主卵的选择性

在室内采用选择性方法 ,研究了甘蓝夜蛾赤眼蜂G品系和F品系对我国几种重要农业害虫的寄主选择性。结果表明 ,G品系对亚洲玉米螟卵和麦蛾卵的选择性无明显差异 ;在对玉米螟卵的选择性上 ,G品系与玉米螟赤眼蜂的差异不明显 ,可作为防治亚洲玉米螟的候选蜂种。F品系对麦蛾卵的选择性强 ,已丧失对玉米螟卵的选择性。G和F品系以及螟黄赤眼蜂对棉铃虫卵的选择性较强 ,而对麦蛾卵的选择性较弱。在对棉铃虫卵的寄主选择性上 ,G和F品系同螟黄赤眼蜂无显著差异 ;但在寄生能力上 ,G和F品系均显著高于螟黄赤眼蜂 ,均可作为防治棉铃虫的候选蜂种。G和F品系以及广赤眼蜂对麦蛾卵的选择性较强 ,而对小菜蛾卵的选择性较弱。

Studies on Host-preference of the Egg Parasite Trichogramma brassicae

The host preferences for host eggs of the Trichogramma brassicae G and F strains were evaluated by choice tests in laboratory. Results showed that there was no significant difference in preference between eggs of Ostrinia furnacalis and Sitotroga cerealella for T. brassicae G strain. No significant difference was found in frequency of contacts and number of parasitized O. furnacalis eggs between T. brassicae G strain and T. ostriniae. T. brassicae G strain may be considered as a candidate for control O. furnacalis. T. brassicae F strain preferred for S. cerealella eggs, and lost the capability to parasitize O. furnacalis eggs. Helicoverpa armigera eggs are preferred over S. cerealella eggs in the two of T. brassicae strains and T. chilonis and number of H. armigera eggs parasitized by the two T. brassicae strains were clearly higher than that of T. chilonis, which is being annually released in practice for H. armigera control. So the two T. brassicae strains may be considered as the candidates for further experiments. S. cerealella eggs are preferred over Plutella xylostella eggs in the two T. brassicae strains and T.