Warm-season turfgrasses, including St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze], are produced and installed as monocultures of single cultivars. Recent research indicates that blending St. Augustinegrass cultivars can increase turfgrass stand resilience to insect pests, establishment of undesired plant species, and abiotic stressors without reducing plant performance. However, effects on specific key turfgrass insect pests are less documented and the mechanisms driving changes in turfgrass stand resilience are unclear. Moreover, it remains unknown if the effects of cultivar blends on biotic resistance vary across St. Augustinegrass’ range. Here, we pair a regional common garden observational field study with a controlled greenhouse experiment to isolate the effects of cultivar blends on the recruitment of predatory arthropods (top-down pest regulation) and on southern chinch bug [Blissus insularis Barber] performance (bottom-up pest regulation). We find that cultivar diversity has no effect on natural enemy recruitment but natural enemies do vary predictably with changes in geographic location. In contrast to our hypothesis, southern chinch bug reached higher densities in cultivar blends compared to cultivar monocultures, although this effect was driven by specific cultivar blends. Despite higher pest densities in turfgrass blends on average, blends of four St. Augustinegrass cultivars maintained a higher percent green cover than cultivar monocultures, suggesting that cultivar blends can persist longer under elevated pest densities compared to cultivar monocultures. Our findings can guide future research focused on blending warm-season turfgrass cultivars as an integrated pest management strategy for more resilient and sustainable turfgrass lawns.

中文翻译：

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研究美国东南部圣奥古斯丁草品种混酿的多营养效应


暖季草坪草，包括圣奥古斯丁草 [Stenotaphrum secundatum （Walt.）Kuntze]，作为单一栽培品种的单一栽培生产和安装。最近的研究表明，混合圣奥古斯丁草栽培品种可以提高草坪草对害虫的适应力，建立不需要的植物物种和非生物压力源，而不会降低植物性能。然而，对特定关键草坪草害虫的影响记录较少，驱动草坪草林分恢复力变化的机制尚不清楚。此外，目前尚不清楚栽培品种混合物对生物抗性的影响是否在 St. Augustinegrass 的范围内有所不同。在这里，我们将区域公共花园观察田间研究与对照温室实验相结合，以分离品种混合物对捕食性节肢动物招募（自上而下的害虫调节）和南方雀虫 [Blissus insularis Barber] 性能（自下而上的害虫调节）的影响。我们发现品种多样性对天敌补充没有影响，但天敌确实会随着地理位置的变化而变化。与我们的假设相反，与品种单一栽培相比，南方雀虫在品种混合物中达到了更高的密度，尽管这种影响是由特定的品种混合物驱动的。尽管草坪草混合物的平均害虫密度较高，但四个圣奥古斯丁草品种的混合物保持了比品种单一栽培更高的绿色覆盖率，这表明与品种单一栽培相比，品种混合物在病虫害密度较高的情况下可以持续更长时间。 我们的研究结果可以指导未来的研究，重点是将暖季草栽培品种混合为一种综合害虫管理策略，以实现更具弹性和可持续性的草坪草坪。