Response of an Invasive Weed, Lepyrodiclis holosteoides Fenzl., and Wheat to Nitrogen and Auxinic Herbicides Applied in Pre and Tank Mix with Photosynthetic Inhibitors

Some herbicides, notably 2,4-D, are efficient at suppressing broadleaf weeds in wheat. No information is available on the effect of L. holosteoides on wheat yield losses. A variety of integrated nitrogen rates (0, 70, 140, and 210 kg N ha(-1) from urea) and postemergence herbicides (2,4-D+MCPA tank mixed with bentazon, bromoxynil+MCPA, bromoxynil +2,4-D, and bentazon+dichlorprop-p) were investigated in winter wheat for their effects on weed control, wheat growth, and yield. A split plot experiment with three replications was conducted in a semiarid environment in 2018-2020. Main-and sub-plots received nitrogen rates and herbicides. All attributes examined had no N-herbicide interactions. L. holosteoides was controlled best with 2,4-D+MCPA tank combined with bentazon (95%), followed by bromoxynil +2,4-D (84%), bentazon+dichlorprop-p (81%), and bromoxynil+MCPA (71%). L. holosteoides's dry weight and leaf area index were 6.67 g m(-2) and 0.049 with 2,4-D+MCPA and bentazon, respectively. Herbicides enhanced wheat output by 12 to 25%. For 60 L. holosteoides plants m(-2), grain yield dropped 25%. Overall, N rates had little influence on L. holosteoides growth and control. Moderate N treatment increased wheat's leaf greenness, area, grain yield, and yield components. The maximum grain yield (6428 kg ha(-1)) was achieved with the application of 147 kg N ha(-1) and bentazon+dichlorprop-p.

Automated summary

Some herbicides, including 2,4-D, effectively suppress broadleaf weeds in wheat. The impact of L. holosteoides on wheat yield losses is unknown. This study investigated the effects of integrated nitrogen rates and postemergence herbicides on weed control, wheat growth, and yield. The results showed that 2,4-D+MCPA tank mixed with bentazon was the most effective in controlling L. holosteoides, followed by bromoxynil+2,4-D, bentazon+dichlorprop-p, and bromoxynil+MCPA. Herbicides improved wheat output by 12-25%. Nitrogen rates had little influence on L. holosteoides growth and control, but moderate nitrogen treatment increased wheat yield.