Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA.
Department of Entomology, University of Kentucky, Lexington, KY.
J Econ Entomol. 2021 Feb 9;114(1):197-200. doi: 10.1093/jee/toaa306.
Melanaphis sacchari Zehntner is a new pest of sweet sorghum in the United States, with the potential to cause complete crop failure. In Kentucky, sweet sorghum is normally planted in early May and harvested in late August or September. Planting sweet sorghum earlier in the season may avoid damaging levels of M. sacchari that develop in late summer. In a 2-yr field study, three different planting dates separated by a month (April, May, and June) were tested for their effect on M. sacchari densities and sweet sorghum yield. April (early) planted sweet sorghum was grown in greenhouses and transplanted to the field. May (mid) and June (late) planted sweet sorghum were direct seeded in the field. Melanaphis sacchari population densities were evaluated weekly starting in June. Sweet sorghum was harvested at the onset of the hard dough stage. Plots were split into two subplots, insecticide or noninsecticide, in the second year to control for planting date effect on yield. Early-planted sweet sorghum had lower aphid densities, but had lower yield relative to mid-planting date, which had the highest yield. Insecticide drenches in 2019 reduced cumulative aphid days in mid-plantings and late plantings, but did not significantly affect yield within planting dates. Seeding sweet sorghum earlier can reduce M. sacchari densities; however, this method alone may not provide the highest yields. We documented that the recommended planting date (May) for Kentucky produced the highest yield.
甘蔗绵蚜是美国甜高粱的一种新害虫，有导致作物绝收的潜在风险。在肯塔基州，甜高粱通常在 5 月初种植，8 月底或 9 月收获。在季节早期种植甜高粱可能会避免 8 月下旬形成的对作物有严重危害水平的甘蔗绵蚜。在为期两年的田间研究中，通过相隔一个月（4 月、5 月和 6 月）的三种不同种植日期来测试它们对甘蔗绵蚜密度和甜高粱产量的影响。4 月（早期）种植的甜高粱在温室中生长，然后移植到田间。5 月（中期）和 6 月（晚期）种植的甜高粱直接在田间播种。从 6 月开始每周评估一次甘蔗绵蚜种群密度。当甜高粱进入硬面团阶段时进行收获。第二年，将每个小区分为两个子小区，用杀虫剂或不用杀虫剂，以控制种植日期对产量的影响。早期种植的甜高粱蚜虫密度较低，但与中期种植日期相比，产量较低，而中期种植日期的产量最高。2019 年，杀虫剂灌根减少了中期和晚期种植的累积蚜虫天数，但在种植日期内对产量没有显著影响。提前播种甜高粱可以降低甘蔗绵蚜的密度；但是，仅采用这种方法可能无法获得最高产量。我们记录到肯塔基州推荐的种植日期（5 月）产生了最高的产量。
