Purdue Weed Scientist Publishes Weed Resistance White Paper
May 4, 2015 Resistant weeds, the appropriate use of herbicides and integrated weed management strategies are highlighted topics in the new white paper, “Overlapping Residual Herbicides” by Purdue University Associate Professor of Weed Science Bryan Young. The white paper is now available here.
“The practice of applying two effective residual herbicide sites of action in combination or the concept of using effective residual herbicides in sequential overlapping applications would both be considered a best management practice to deter the development of herbicide-resistant weeds,” writes Young.
The white paper includes research related to glyphosate-resistance in reference to the three most problematic weeds confronting famers in the major corn and soybean production areas of the United States: waterhemp, Palmer amaranth and horseweed (or marestail). These aggressive weed species can reduce soybean yields by 40 percent or more and have become problematic for growers due to prolific seed production, continuous weed emergence throughout the growing season, ease of seed dispersal and ease of overcoming or escaping herbicide-based management tactics. Soil applied residual herbicides are the most frequently recommended because of the multiple benefits, which are further explored in the white paper.
“The most common approach to managing herbicide-resistant weed species such as glyphosate-resistant horseweed, Palmer amaranth or waterhemp has been the use of an effective alternative herbicide as a tank-mixture with glyphosate as a residual herbicide preceding a postemergence application of glyphosate, or a combination of both,” writes Young.
Young concludes the white paper by summarizing that “without the use of residual herbicides for weed management, farmers are risking lost crop yield due to weed competition and continued movement towards more weed resistance to postemergence herbicides. However, only those weed management programs that carefully select the most effective soil residual herbicides and apply them in a manner to optimize their contribution to weed management (i.e., overlapping residuals) will realize the greatest benefits.”
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