Influence of Spring Herbicide Applications on Winter Weed Emergence in Corn and Soybean Production Systems

Abstract

Experiments were conducted in Indiana to assess the densities of winter weed species at 180 and 310 days when the soil‐applied residual herbicides were applied in combination with glyphosate in corn (Zea mays) and soybean (Glycine max) production systems. Weed densities were higher at 180 days compared to 310 days, irrespective of the weed species at SEPAC site. In corn systems, additional application of atrazine did not decrease the weed densities at both sites. However, in few instances, cloransulam‐methyl reduced the shepherd's purse and smallflower buttercup densities as compared to non‐treated check in soybean systems. In most instances, the residual herbicides applied as PRE or POST did not decrease the weed densities significantly at 180 days or at 310 days after application compared to systems that did not utilize residual herbicides.