Nowatzki Timothy M, Tollefson Jon J, Bailey Theodore B
Department of Entomology, Iowa State University, Ames 50011-3140, USA.
J Econ Entomol. 2002 Jun;95(3):570-7. doi: 10.1603/0022-0493-95.3.570.
Planting corn, Zea mays L., in row spacings less than the conventional width of 76 cm has been shown to increase grain yields. This study was conducted to determine if row spacing and plant density affected corn rootworm, Diabrotica virgifera virgifera LeConte and D. barberi Smith & Lawrence, adult emergence, larval injury to the roots, and plant tolerance to injury. Field experiments were conducted at Ames and Nashua, IA, in 1998, 1999, and 2000. Treatments were row spacings of 38 and 76 cm, and plant populations of 64,500 and 79,600 plants per hectare. Adult emergence was 31% greater in 38 cm compared with 76-cm rows. However, root injury was not significantly different between row spacings or plant populations. Row spacing alone did not significantly influence tolerance to injury, measured as root size and the amount of root regrowth. However, at one environment where precipitation was low, plants in 38-cm rows produced 25% more regrowth compared with plants in 76-cm rows. Root dry weight and regrowth were suppressed by 16 and 32%, respectively, at the high plant population. Although lodging was 51% lower in the 38-cm rows compared with the 76-cm rows, grain yields were not significantly different between row spacings. Reducing the row spacing of field corn from 76-38 cm should not increase the potential for injury from corn rootworm larvae.
种植行距小于传统的76厘米的玉米（Zea mays L.）已被证明可提高谷物产量。本研究旨在确定行距和种植密度是否会影响玉米根虫（Diabrotica virgifera virgifera LeConte和D. barberi Smith & Lawrence）的成虫羽化、幼虫对根部的伤害以及植株对伤害的耐受性。1998年、1999年和2000年在爱荷华州的艾姆斯和纳舒厄进行了田间试验。处理包括38厘米和76厘米的行距，以及每公顷64500株和79600株的种植密度。与76厘米行距相比，38厘米行距的成虫羽化率高31%。然而，行距或种植密度之间的根部伤害没有显著差异。仅行距对以根大小和根再生量衡量的伤害耐受性没有显著影响。然而，在一个降水较少的环境中，38厘米行距的植株比76厘米行距的植株再生量多25%。在高种植密度下，根干重和再生量分别被抑制了16%和32%。尽管38厘米行距的倒伏率比76厘米行距低51%，但行距之间的谷物产量没有显著差异。将大田玉米的行距从76厘米减小到38厘米不应增加玉米根虫幼虫造成伤害的可能性。
