Suppression of Annual Bluegrass Seedheads with Mefluidide, Ethephon, and Ethephon plus Trinexapac‐Ethyl on Creeping Bentgrass Greens

Abstract

Annual bluegrass (Poa annua L.) is a problematic weed on creeping bentgrass (Agrostis stolonifera L.) putting greens. Annual bluegrass produces extensive seedheads in spring, and plant growth regulators (PGRs) are frequently used to suppress seedhead formation. This study investigated the effects of single and sequential applications of mefluidide, maleic hydrazide, and ethephon alone or in combination with trinexapac‐ethyl (TE), on annual bluegrass seedhead formation. A secondary objective evaluated whether addition of TE enhanced the efficacy of ethephon while improving the safety on creeping bentgrass. Three independent studies were established on golf course greens during a 2‐yr period, with initial PGRs application before annual bluegrass seedhead formation. Regardless of PGR treatment, single or sequential applications in all studies showed no differences in annual bluegrass seedhead suppression. Ethephon‐containing treatments provided the best seedhead suppression with up to 95% reduction. No PGR treatments caused visible phytotoxicity to creeping bentgrass following single applications. Sequential applications of both mefluidide and maleic hydrazide caused significant phytotoxicity to creeping bentgrass for up to 3 wk after initial treatment (WAIT). With the exception of one evaluation date in the third study, tank mixture of TE with ethephon had little effect on annual bluegrass seedhead suppression. Tank‐mixing TE with ethephon marginally enhanced turf quality of creeping bentgrass up to 6% compared to ethephon alone.

Adding a late fall application of Proxy (ethephon) before two traditional spring applications improves seedhead control of annual bluegrass

“…Similar to Askew (2017) and Haguewood et al (2013), Proxy alone did not cause turf injury regardless of application timing. Although Dernoeden and Pigati (2009) reported crown elevation and scalping of CBG after Proxy was applied in mid-summer heat, neither was seen in these studies.…”

Chemical plant protectants and plant growth regulator effects on annual bluegrass survival of ice cover

“…Plant growth regulators are used primarily in turfgrass management to reduce above ground growth, thereby reducing mowing requirements, or to inhibit seed head production. Mefluidide inhibits cell elongation and division and is applied to limit ABG flowering and seed head production in golf course putting greens in the spring (Haguewood, Song, Smeda, Moss, & Xiong, ; Tautvydas, ). The mode of action of mefluidide was only recently determined to be associated with inhibition of 3‐ketoacyl‐CoA synthase, which is involved in very long chain fatty acid synthesis (Tresch, Heilmann, Christiansen, Looser, & Grossmann, ).…”

“…Plant growth regulators are used primarily in turfgrass management to reduce above ground growth, thereby reducing mowing requirements, or to inhibit seed head production. Mefluidide inhibits cell elongation and division and is applied to limit ABG flowering and seed head production in golf course putting greens in the spring (Haguewood, Song, Smeda, Moss, & Xiong, 2013;Tautvydas, 1984).…”

Plant Growth Regulators Applied in Winter Improve Annual Bluegrass (Poa annua) Seedhead Suppression on Golf Greens

“…Golf course superintendents typically employ chemical or mechanical treatments to reduce annual bluegrass seedhead density on greens (Haguewood et al 2013; Inguagiato et al 2010). Ethephon and mefluidide have been the most commonly used chemicals to suppress annual bluegrass seedheads on golf greens in the past few decades (Eggens et al 1989; Haguewood et al 2013; Inguagiato et al 2010). These plant growth regulators, however, have had widely variable effects on annual bluegrass seedhead suppression in different trials.…”