Fall Applications of Proxy (Ethephon) Suppress Spring Seedheads of ‘Meyer’ Zoysiagrass

Core Ideas Early fall Proxy (ethephon) applications effectively suppress Meyer zoysiagrass seedheads in spring. Apply Proxy in late‐September when days are approximately 12 hours long to suppress zoysiagrass seedheads. Tank‐mixtures of Proxy with large patch fungicides reduce application labor and equipment costs.‘Meyer’ zoysiagrass ( Zoysia japonica Steud.) is used on golf courses throughout the transitional climatic zone because of its aesthetic and functional quality and tolerance to abiotic stresses. However, a key problem with Meyer zoysiagrass is that it produces seedheads in the spring that reduce aesthetics and increase golf course maintenance costs. The objective of this experiment was to quantify the efficacy of Proxy (ethephon) on Meyer zoysiagrass seedhead suppression at three locations when applied in fall before winter dormancy and in spring prior to seedhead production. The early fall application timing of Proxy provided > 90% suppression of zoysiagrass seedheads with < 10% injury. Late fall and spring Proxy applications provided little seedhead suppression. The early fall application timing that successfully suppressed Meyer zoysiagrass seedheads in our experiment was applied from 23 to 29 September across locations to 100% green zoysiagrass; on dates with a photoperiod of 11.9 to 12.1 h; and following the accumulation of < 14 cooling degree days (20°C base temperature). This research provides turf managers insight on how to best suppress Meyer zoysiagrass seedhead production.