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证据表明引进的寄生蜂Collyria coxator(Villers)正在对特拉华州的欧洲麦茎蜂Cephus Pygmaeus(L.)提供适当的生物防治。1982年C. coxator的平均寄生率为44％(范围为0—62％),1983年为52％(范围为27—82％)。此种条件下欧洲麦茎蜂对小麦的为害率约为2％。秋收以后沿着田边对欧洲麦茎蜂幼虫进行取样,能够提供最准确的C. coxator寄生率。单独的田块内似乎存在着强烈的非密度制约的寄生蜂—寄主关系,而与田块大小无关。然而在田间,以大田规模为基础,有些资料却暗示出一种具密度制约的寄生蜂—寄主关系。
Evidence indicates that the introduced parasitic wasp Collyria coxator (Villers) is providing proper biological control of the Cephus Pygmaeus (L.), a Delaware state. The average co-occurrence of C. coxator in 1982 was 44% (range 0 - 62%) and 52% (range 27-82%) in 1983. Under such conditions, the damage rate of European wheat stems to wheat is about 2%. Sampling the European wheat bee larvae along the fields after the autumn harvest provides the most accurate C. coxator parasitism. There seems to be a parasitic wasp-host relationship in the individual plots that appears to be strongly non-density-restricted, irrespective of field size. However, in the field, based on the size of the field, some data suggest a parasitic wasp-host relationship with density constraints.