School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA.
Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE.
J Econ Entomol. 2020 Aug 13;113(4):1831-1838. doi: 10.1093/jee/toaa093.
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.
历史上，小麦茎蜂（Cephus cinctus Norton）是大平原北部春小麦种植区的一种害虫。然而，在上世纪 80 年代，人们发现它在蒙大拿州的冬小麦田中泛滥成灾。上世纪 90 年代，内布拉斯加州西部首次发现了虫害，此后，虫害已蔓延至内布拉斯加州狭长地带的全境。幼虫通过蛀食茎干造成损害，但导致茎干弯曲倒伏、无法收获的茎干环割则会造成最大的产量损失。小麦茎蜂的生物学和物候学在其分布范围的北部地区已有详细描述，但在科罗拉多州、怀俄明州东南部和内布拉斯加州却有所缺失。本研究通过扫网和幼虫取样的方法，描述了内布拉斯加州冬小麦田中小麦茎蜂的物候和扩散情况。在这项为期 2 年的研究中，成虫活动于 5 月 23 日开始，6 月 21 日结束。2014 年雌雄比为 2.32:1，2015 年为 0.46:1。雌雄两性在麦田内均表现出边缘效应，靠近田边的密度更高。雄性小麦茎蜂的边缘效应比雌性更强。无论雌性小麦茎蜂的密度如何，小麦茎蜂幼虫的密度都存在边缘效应。这些信息对内布拉斯加州和邻近地区制定小麦茎蜂管理计划将非常有用。
