Antagonistic effects of paraquat and glufosinate on the efficacy of glyphosate for the management of Cynodon dactylon

Pot studies were conducted during the Kharif season of 2024 and 2025 at ICAR-Indian Institute of Wheat and Barley Research, Karnal, to identify the effective herbicides for controlling Cynodon dactylon. The tested herbicide treatments include: glyphosate at 2.0, 4.0 and 6.0 kg/ha; paraquat at 0.5 kg/ha and glufosinate 0.4 kg/ha and tank mixtures of glyphosate with paraquat and glufosinate. Paraquat and glufosinate were less effective in controlling C. dactylon, while glyphosate provided effective and complete control (100%) at a dose of = 4.0 kg/ha. Strong antagonistic effect was observed with the tank mix combination of paraquat with glyphosate. Slight reduction in the efficacy of glyphosate was also observed when glufosinate was tank mixed with glyphosate. Thus, glyphosate = 4.0 kg/ha can be used for managing C. dactylon in non-cropped areas or as a pre-plant control option in no-till system. The mixing of glyphosate with paraquat and glufosinate should be avoided.