Distribution of glyphosate-resistant Amaranthus spp. in Nebraska.

The intensive glyphosate selection pressure exerted in soybean (Glycine max) fields in eastern Nebraska is one of the major factors causing widespread occurrence of glyphosate resistance in common waterhemp in the state. The relatively low frequency of glyphosate-resistant Palmer amaranth in the state highlights the importance of the application timing and the adoption of multiple modes of action in weed management practices to delay the evolution of glyphosate resistance. © 2017 Society of Chemical Industry.