Late‐Season Bermudagrass Control with Glyphosate, Fluazifop, and Mesotrione Combinations

Abstract

Core Ideas More information is needed to improve late‐season bermudagrass control strategies in the Central Plains region of the United States. A single autumn application of glyphosate reduces bermudagrass cover the following spring. Bermudagrass control with a single autumn application of glyphosate was not improved by adding fluazifop, mesotrione, or both. Multiple summer applications of glyphosate (N‐(phosphonomethyl)glycine) are commonly recommended for bermudagrass (Cynodon spp.) control. However, this regime results in an extended period of displeasing and nonfunctional turfgrass, and is not ideal for spring establishment. An autumn glyphosate application prior to winter dormancy can control bermudagrass and may benefit spring establishment projects. However, research is needed to more precisely define the parameters of efficacious late‐season herbicide applications for bermudagrass control as it transitions into dormancy. Therefore, our objective was to examine late‐season bermudagrass removal using combinations of glyphosate, fluazifop‐p‐butyl (fluazifop) (Butyl (R)‐2‐[4[[5‐(trifluoromethyl)‐2‐pyridinyl]oxy]phenoxy]propanoate), and mesotrione (2‐(4‐methylsulfonyl‐2‐nitrobenzoyl)‐1,3‐cyclohexanedione). Experiments were initiated in October 2013 at the Rocky Ford Turfgrass Research Center in Manhattan, KS, on mature ‘Midlawn’ hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy], and at Stagg Hill Golf Course in Manhattan, KS, on mature common bermudagrass [C. dactylon (L.) Pers.]. Seven herbicide treatments containing combinations of glyphosate, fluazifop, and mesotrione were evaluated. Green bermudagrass cover (0–100%) was visually estimated when treatments were applied and every 14 d after application. Only treatments containing glyphosate reduced the green cover of bermudagrass at each site the following year. Across all ratings dates and locations, adding mesotrione, fluazifop, or both to glyphosate did not further reduce green bermudagrass cover. Overall, results indicate that a single autumn application of glyphosate prior to bermudagrass dormancy reduces bermudagrass cover the following spring. The significant reduction at spring green‐up may allow turf managers to make additional applications in the spring for increased control before spring establishment.