Redroot pigweed (Amaranthus retroflexus L.) and common lambsquarters (Chenopodium album L.) are two of the world’s worst broadleaf weeds. In this study, the effects of (2-(N-((4,6-dimethoxypyrimidin-2-yl)carbamoyl)sulfamoyl)- 4-formamido-N,N-dimethylbenzamide) (foramsulfuron) and (2-[(4,6-dimethoxypyrimidin-2-yl)carbamoylsulfamoyl]-N,Ndimethylpyridine- 3-carboxamide) (nicosulfuron) applied alone or tank-mixed with ((2,4-dichlorophenoxy) acetic acid plus (4-chloro-2-methylphenoxy) acetic acid) (2,4-D + MCPA) at different ratios on redroot pigweed and common lambsquarters control in corn (Zea mays L.) were examined. Field experiments were conducted in 2011 and 2012 at the Ferdowsi University of Mashhad in Mashhad, Iran. These experiments were conducted as a randomized complete block design with three replications. Results indicated that foramsulfuron and nicosulfuron (sulfonylurea herbicides) applied in tank-mix with 2,4-D + MCPA controlled redroot pigweed and common lambsquarters from 78 to 100%, depending on herbicide doses. Corn grain yield was less when sulfonylurea herbicides were applied alone compared to when they were applied with 2,4-D + MCPA. Corn grain yield was not different when 2,4-D + MCPA were tank-mixed at higher rates with sulfonylurea herbicides compared to the weed-free check. Tank-mixtures of foramsulfuron + 2,4-D + MCPA caused less injury and yield loss than nicosulfuron + 2,4-D + MCPA.

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