Herbicide Diversity Keeps Resistant Weeds Away

Using different herbicide application strategies might be expensive, but according to researchers at the Purdue University, this approach will significantly reduce the population and density of glyphosate resistant weeds. Glyphosate, the active ingredient in the popular herbicide Roundup, is effective in keeping unwanted weeds in check. Excess usage of Roundup, however, has led to weeds that also are resistant to the herbicide.

Bill Johnson and colleagues studied marestail or horseweed, the first weed to develop resistance to glyphosate. Johnson's study found that using a variety of herbicides in addition to Roundup before planting and alternating between Roundup and other herbicides in corn can significantly reduce herbicide-resistant marestail. Their work appears in the current issue of Weed Science.

Johnson said: "Glyphosate-resistant marestail develops very quickly in a field. Populations reach staggering levels of infestation in about two years after it is first detected… [This] showed that a weed-management system that is solely reliant on glyphosate is starting to break down. However, a system that incorporates other herbicides with glyphosate can be sustainable for quite some time."

The original story is available at http://news.uns.purdue.edu/x/2009b/090713JohnsonManagement.html