Brown patch (caused by various Rhizoctonia and Rhizoctonia-like species) is a major summer disease for several cool-season turfgrass species, including creeping bentgrass (CBG) (Agrostis stolonifera L.), colonial bentgrass (CLBG) (Agrostis capillaris L.), perennial ryegrass (PRG) (Lolium perenne L.), and turf-type tall fescue (TTTF; [Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.]). Elevated nitrogen (N) rates are suggested to enhance development of brown patch symptoms. A controlled environment study was conducted to determine the influence of two N rates among four cool-season turfgrass species maintained at 1.9 cm after inoculation with R. solani. Field-grown plants of four CBG cultivars, a CLBG cultivar, a PRG blend, and two TTTF cultivars were fertilized weekly, totaling 49 and 196 kg N ha⁻¹ across four applications. Turfgrass responses were measured as relative growth rate, brown patch severity, and seasonal brown patch using area under the disease progress curve (AUDPC). On average, peak brown patch severity among the species and cultivars was between 22.6% and 68.1% for Raptor III TTTF and Penn A-1 CBG, respectively. Turf-type tall fescue cultivars decreased brown patch by 61% compared to CBG, CLBG, and PRG. The lower N rate reduced brown patch AUDPC by 17% and 33% for CBG and PRG, respectively, but N rate generally had no effect for CLBG and TTTF. These results reinforce the importance of planting disease-resistant species and cultivars. Additionally, N rate may be an important factor affecting brown patch severity for select intensively managed turfgrass species.

中文翻译：

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棕斑严重程度受冷季型草坪草品种、品种和施氮量的影响


褐斑病（由各种丝核菌和类丝核菌物种引起）是几种冷季型草坪草物种的主要夏季病害，包括匍匐翦股颖 (CBG) (Agrostis stolonifera L.)、群居翦股颖 (CLBG) (Agrostis capillaris L.) 、多年生黑麦草 (PRG) (Lolium perenne L.) 和草皮型高羊茅 (TTTF; [Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.])。建议提高氮 (N) 含量以促进褐斑症状的发展。进行了一项受控环境研究，以确定两种氮施用量对接种立枯丝核菌后保持在 1.9 厘米的四种冷季型草坪草品种的影响。四个 CBG 品种、一个 CLBG 品种、一个 PRG 混合物和两个 TTTF 品种的田间种植植物每周施肥，四次施肥总计分别为 49 和 196 千克氮公顷 ⁻¹ 。使用疾病进展曲线下面积 (AUDPC) 来测量草坪草反应，包括相对生长率、棕色斑块严重程度和季节性棕色斑块。平均而言，Raptor III TTTF 和 Penn A-1 CBG 的物种和品种之间的峰值棕色斑块严重程度分别在 22.6% 和 68.1% 之间。与 CBG、CLBG 和 PRG 相比，草坪型高羊茅品种的棕色斑块减少了 61%。较低的施氮量使 CBG 和 PRG 的棕色斑块 AUDPC 分别降低了 17% 和 33%，但施氮量通常对 CLBG 和 TTTF 没有影响。这些结果强调了种植抗病物种和品种的重要性。此外，对于精选的集约化管理的草坪草品种而言，施氮量可能是影响褐斑严重程度的重要因素。