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

Abstract

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.

Irrigation following a fall Proxy (ethephon) application affects spring seedhead suppression of Meyer zoysiagrass

“…Consistent with a previous report by Patton et al. (2018), fall Proxy application with no irrigation afterwards reduced spring seedheads by up to 45% compared with the untreated (Table 1). At both locations, irrigating after a Proxy application influenced the cover and quantity of seedheads, where 1.0 inches of irrigation increased seedhead coverage compared with no postapplication irrigation.…”

“…Meyer zoysiagrass provides an excellent turf surface for golf course fairways because of its high turf quality, durability, low N fertility requirements, and tolerance of abiotic stresses (Patton, Schwartz, & Kenworthy, 2017). However, spring seedhead (inflorescence) production causes a decline in turf aesthetics and an increase in maintenance costs (Brosnan, Breeden, Elmore, Patton, & Weisenberger, 2012; Patton, Schortgen, Hoyle, Harrell, & Reicher, 2018). A recent study demonstrated that a fall application of Proxy [ethephon (2‐chloroethylphosphonic acid); Bayer Environmental Science] plant growth regulator can be an effective option to suppress spring seedhead production in Meyer zoysiagrass (Patton et al., 2018).…”

“…However, spring seedhead (inflorescence) production causes a decline in turf aesthetics and an increase in maintenance costs (Brosnan, Breeden, Elmore, Patton, & Weisenberger, 2012; Patton, Schortgen, Hoyle, Harrell, & Reicher, 2018). A recent study demonstrated that a fall application of Proxy [ethephon (2‐chloroethylphosphonic acid); Bayer Environmental Science] plant growth regulator can be an effective option to suppress spring seedhead production in Meyer zoysiagrass (Patton et al., 2018). This fall timing is within the same application window recommended for preventative fungicide applications of Rhizoctonia large patch disease (RLPD) [ Rhizoctonia solani Kuhn Anastomosis Group (AG)‐2‐2 LP], which is the primary disease affecting zoysiagrass (Patton et al., 2018).…”

Registration of ‘DALZ 1308’ zoysiagrass

“…In the fall seasons of 2015 and 2016, DALZ 1308 produced practically zero seedheads in comparison to either check. Recently, the use of plant growth regulators has resulted in the suppression of seedhead emergence in Z. japonica (Brosnan et al., ; Patton et al., ), but the efficacy and timing of application remain to be tested on DALZ 1308 ( Z. minima × Z. matrella hybrid). Unlike Diamond, DALZ 1308 does not produce seedheads in Dallas, TX, in the fall season, which would likely result in reduced need for the use of plant growth regulators for fall seedhead suppression.…”

“…In the fall seasons of 2015 and 2016, DALZ 1308 produced practically zero seedheads in comparison to either check. Recently, the use of plant growth regulators has resulted in the suppression of seedhead emergence in Z. japonica (Brosnan et al, 2012;Patton et al, 2018), but the efficacy and timing of application remain to…”