Dose responses of silvery-thread moss (Bryum argenteum) to carfentrazone-ethyl. (8th August 2021)

• Record Type: Journal Article
• Authors: Raudenbush, Zane; Keeley, Steven J.; Thompson, Cole; Jugulam, Mithila
• Is Part Of: Weed technology. Volume 35:Number 4(2021)
• Page Start: 611
• Page End: 617
• Publication Date: 2021-08-08
• Subjects: Carfentrazone-ethyl -- silvery-thread moss -- Bryum argenteum Hedw. -- creeping bentgrass -- Agrostis stolonifera L.; Protoporphyrinogen oxidase (PPO) -- contact herbicides -- golf course weed control -- golf course putting greens -- golf course tees -- bryophytes; Weeds -- Periodicals; Weeds -- Control -- Periodicals; 632.5
• DOI: 10.1017/wet.2021.42
• Languages: English
• ISSNs: 0890-037X

Abstract

Abstract: Carfentrazone-ethyl is one of few herbicides labeled for control of silvery-thread moss (STM) in golf course putting greens, but common use rates are up to three times higher than for broadleaf weeds. Our objective was to determine the efficacy of a single POST application of carfentrazone-ethyl for STM control in greenhouse and field dose response studies. In the greenhouse, carfentrazone-ethyl was applied at 0, 14, 28, 56, 112, and 224 g ai ha –1 to pots containing established STM and creeping bentgrass. Percent gametophyte injury was visually estimated at 14, 28, 49, and 77 d after treatment (DAT). Shoot viability was determined by excising shoots from treated pots and plating them in Petri dishes containing sand. The 28- and 49-DAT ED90 (doses required to cause 90% gametophyte injury) were 26.8 and 54.3 g ha –1, respectively; both of these doses are substantially lower than the label rates for long- and short-term control, respectively. All doses reduced the viability of transplanted shoots at 10 DAT compared to untreated STM; however, regrowth occurred in all Petri dishes by 17 DAT. Field studies were initiated in Manhattan, KS and San Luis Obispo, CA to corroborate greenhouse results. Averaged across locations, carfentrazone-ethyl applied at 56 and 112 g ha –1 caused 76% and 84% STM injury at 14 DAT, but STM injury quickly lessened to 45% and 48% by 28 DAT, respectively. In greenhouse and field studies, STM recovery did not occur until 2 wk after treatment (WAT), which indicates the label-stipulated application interval of 2 wk is too short. Our research suggests that 56 g ha –1 can provide similar burndown control of STM as compared to the highest label rate (112 g ha –1 ), and turfgrass managers should consider extending the reapplication interval to 3 or 4 wk when moss recovery is observed.