Abstract Historically, the wheat stem sawfly, Cephus cinctus Norton was a pest in spring wheat-growing regions of the northern Great Plains. However, in the 1980s, it was found infesting winter wheat fields in Montana. Infestations were first detected in western Nebraska in the 1990s, and have since spread throughout the Nebraska Panhandle. Larval damage occurs from stem-mining, but stem girdling that results in lodged stems that are not harvested results in the greatest yield losses.The biology and phenology of the wheat stem sawfly are well described in the northern portion of its range, but they are lacking in Colorado, southeast Wyoming, and Nebraska. In this study, the phenology and dispersal of the wheat stem sawfly in Nebraska winter wheat fields is described using sweep net and larval sampling. During this 2-yr study, adult activity began on May 23 and ended on June 21. Adult sex ratios were 2.32 males per female in 2014 and 0.46 males per female in 2015. Both sexes demonstrated an edge effect within the wheat fields, with greater densities near the field edge.The edge effect was stronger for male wheat stem sawfly than females. Wheat stem sawfly larval density also had an edge effect, regardless of the density of female wheat stem sawfly present.This information will be useful for developing management plans for the wheat stem sawfly in Nebraska and neighboring regions.

中文翻译：

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小麦茎锯蝇（膜翅目：Cephidae）到内布拉斯加州冬麦田的物候和扩散

摘要 历史上，小麦茎叶蜂Cephus cinctus Norton 是大平原北部春小麦产区的害虫。然而，在 1980 年代，人们发现它侵扰蒙大拿州的冬小麦田。1990 年代在内布拉斯加州西部首次发现虫害，此后蔓延到整个内布拉斯加州狭长地带。茎部开采会造成幼虫损害，但茎环剥落导致茎部未收获而造成最大的产量损失。小麦茎叶蜂的生物学和物候学在其分布范围的北部得到了很好的描述，但它们是在科罗拉多州、怀俄明州东南部和内布拉斯加州缺乏。在这项研究中，使用扫网和幼虫采样描述了内布拉斯加州冬小麦田中小麦茎叶蜂的物候和扩散。在这项为期两年的研究中，成虫活动从 5 月 23 日开始，到 6 月 21 日结束。 2014 年成虫性别比为 2.32 雄/雌，2015 年为 0.46 雄/雌。两性在麦田内都表现出边缘效应，靠近田边的密度更大。雄性小麦茎叶蜂的边缘效应强于雌性。无论雌性小麦茎叶蝇的密度如何，小麦茎叶蜂幼虫密度也具有边缘效应。该信息将有助于为内布拉斯加州和邻近地区的小麦茎叶蝇制定管理计划。