Iowa State University reported the existence of glyphosate-resistant common waterhemp in 1998, and it is clear that the evolution of glyphosate-resistant weeds is increasing at a notable rate. However, the relative economic importance of glyphosate-resistant weed biotypes in Iowa has to date not been of major consequence. However, the lack of significant glyphosate resistance in Iowa weed communities can be anticipated to change based on reports and observations of glyphosate-resistant weed biotypes in neighboring states and anecdotal comments from the agricultural community. Furthermore, the occurrence of Asiatic dayflower and other weed population shifts attributable to selection pressure from glyphosate use is more frequent.