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1989～1996年,在杭州郊区调查了十字花科蔬菜上小菜蛾的寄生昆虫天敌种类和被寄生率。共发现6种原寄生天敌,即赤眼蜂Trichogramma sp.、菜蛾绒茧蜂Cotesia plutellae、颈双缘姬蜂Diadromus collaris、菜蛾啮小蜂Oomyzus sokolowskii、螟蛉埃姬蜂Itoplectis naranyae、无脊大腿小蜂Brachymeria excavinata,以及7种菜蛾绒茧蜂的重寄生蜂。卵期的寄生率较低,幼虫和蛹期的寄生率较高,每年6～7月和10～11月是两个发生高峰,高峰期的寄生率一般在20％～60％,最高时达到80％以上。菜蛾绒茧蜂、菜蛾啮小蜂和颈双缘姬蜂是3种主要天敌。在田间,菜蛾绒茧蜂终年可见;菜蛾啮小蜂活动期为5～10月,10～11月开始陆续以预蛹在寄主体内进入休眠越冬,翌年4～5月间才羽化出蜂;而颈双缘姬蜂每年只在5～7月有较高的寄生率,其它季节较少见。调查时发现,萝卜地和芥菜地的寄生率通常比甘蓝地和小白菜地的高,而且同期两种菜蛾幼虫期寄生蜂即菜蛾绒茧蜂和菜蛾啮小蜂的寄生率,当其中一种较高时,另一种相对较低,表明两寄生蜂之间可能有一定的竞争排斥作用。
From 1989 to 1996, the species and parasitism of parasitic insects on the diamondback moth (Plutella xylostella) in cruciferous vegetables were investigated in the suburbs of Hangzhou. A total of 6 species of natural parasites were identified, Trichogramma sp., Cotesia plutellae, Diadromus collaris, Oomyzus sokolowskii, Itoplectis naranyae, Brachymeria excavinata, as well as seven parasitoid wasps of the parasitoid Apanteles plutellae. The parasitism rate of egg stage is low, the parasitism rate of larvae and pupal stage is high, and the peak occurs from June to July and from October to November each year. The peak parasitism rate usually ranges from 20% to 60% 80% or more. The parasitoid Apanteles plutellae, Plutella xylostella and the Apis cerana cerana were the three main natural enemies. In the field, the parasitoid Aphelenchoides moths can be seen all year round. The activity period of the Aphelenchoides moths is from May to October. From October to November, it began to fall dormant in the host through pre-pupae. The bee developed from April to May the following year ; While the two-necked Phyllostachys pubescens each year only in May to July have a higher parasitism rate, rare in other seasons. The survey found that radish and mustard in the parasitism rate is usually higher than cabbage and cabbage, and the parasitic rates of parasitoids of the parasitoid larvae of the two species of Plutella xylostella, One of them is higher and the other is relatively low, indicating that there may be some competitive exclusion between the two parasitoids.