Source: Iowa State University

A large percentage of corn fields have not been treated with pre-emergence herbicides this year due to low glyphosate prices and early planting. Iowa State University reminds producers that early removal of weeds is essential in order to protect yield potential of the crop.

Early in the season a plant's demand for these resources is small, therefore minimizing competition between the crop and weed.  However, recent research has documented that non-competitive interactions between weeds and corn very early in the season can significantly affect corn growth, development and yield potential, prior to the onset of significant competition for resources.

Original press release