Interaction of foramsulfuron or nicosulfuron with 2,4-D + MCPA on important broadleaf weeds in corn (Zea mays L.)

Abstract

Interaction of binary mixture of the two sulfonylurea herbicides: foramsulfuron or nicosulfuron with 2,4-D + MCPA, was evaluated in greenhouse experiments during 2010 and 2011 applying the additive dose model. Plants of redroot pigweed, common lambsquarters, common purslane and black nightshade were sprayed with seven doses of herbicides alone and in binary fixed-ratio mixtures. In total, 35 binary mixtures were studied in 7 separate experiments at ED90 response level. Results indicated that mixture of foramsulfuron + 2,4-D + MCPA was synergistic on redroot pigweed compared to additive interaction between nicosulfuron and 2,4-D + MCPA. Mixture of foramsulfuron + 2,4-D + MCPA was slightly antagonistic on common lambsquarters and an additive interaction was observed with both foramsulfuron and nicosulfuron + 2,4-D + MCPA on common purslane. Finally, the mixture of foramsulfuron or nicosulfuron + 2,4-D + MCPA on black nightshade was antagonistic especially in mixtures where the ratio of sulfonylurea herbicides was more than 2,4-D + MCPA. Totally, 2,4-D + MCPA in mixture with sulfonylurea herbicides especially foramsulfuron provided better control of redroot pigweed in comparison with herbicides applied alone and other herbicide mixtures on weeds. Abbreviations: 2,4-D + MCPA: ((2,4-Dichlorophenoxy) acetic acid plus (4-chloro-2-methylphenoxy) acetic acid); ADM: additive dose model; a.i.: active ingredient; ALS: acetolactate synthase; DAT: days after treatment; ED: effective dose; Foramsulfuron: (2-(N-((4,6-dimethoxypyrimidin-2-yl)carbamoyl)sulfamoyl)-4-formamido-N,N-dimethylbenzamide); Nicosulfuron: (2-[(4,6-dimethoxypyrimidin-2-yl)carbamoylsulfamoyl]-N,N-dimethylpyridine-3-carboxamide).

Keywords

• 2,4-D + MCPA
• additive dose model
• antagonism
• fixed-ratio mixture
• sulfonylurea herbicides
• synergism