Annual bluegrass control in bermudagrass using dimethenamid and pendimethalin

Abstract

AbstractA 2‐yr field experiment was conducted at three locations across Tennessee during 2017–2018 to determine if early‐postemergence (EPOST) applications of FreeHand [pendimethalin (3,4‐dimethyl‐2,6‐dinitro‐N‐pentan‐3‐ylaniline) + dimethenamid (2‐chloro‐N‐[2,4‐dimethylthiophen‐3‐yl]‐N‐[1‐methoxypropan‐2‐yl]acetamide)] could control annual bluegrass (Poa annua L.)(ABG) similar to Kerb SC [pronamide (3,5‐dichloro‐N‐[2‐methylbut‐3‐yn‐2‐yl]benzamide)] and Princep [simazine (6‐chloro‐2‐N,4‐N‐diethyl‐1,3,5‐triazine‐2,4‐diamine)]. Across all locations and years, EPOST applications of FreeHand at 200 lb acre–1 controlled ABG by 88 to 100% 23 wk after the initial treatment, more than or equal to Kerb SC and Princep. Follow‐up research was conducted in Knoxville, TN, during 2018–2019 to compare the efficacy of FreeHand applied EPOST with Pendulum AquaCap (pendimethalin) and Tower (dimethenamid) applied individually. Sequential EPOST applications of Tower controlled ABG similar to FreeHand on all ratings dates, whereas single applications of Tower resulted in less control. Annual bluegrass control efficacy with EPOST applications of Pendulum AquaCap varied over years. Over the course of eight trials, EPOST applications of FreeHand at 200 lb acre–1 controlled ABG by 88 to 100%, suggesting that it is a new option turfgrass managers can use to control ABG in bermudagrass (Cynodon spp.).