A study published in the journal “Weed Science”on May 2 shed light on the prominence of giant ragweed and its contribution to crop loss across the Corn Belt.
The report, which was conducted by the U.S. Department of Agriculture’s Agricultural Research Service found that giant ragweed is spreading, and it’s becoming more herbicide resistant.
Currently, it’s spreading fast throughout crop fields in the east-central U.S. Corn Belt. The weed is commonly found near the upper Mississippi River, as well as north of the Ohio River. About 60 percent of the counties represented in the report claim that ragweed populations have been resistant to ALS-inhibiting herbicides, to glyphosate or to both.
Researchers also discovered that populations of giant ragweed were most dominant in areas where there was an abundance of non-crop environments, as well as seed-burying earthworms.
“Managing giant ragweed in non-crop areas could reduce its migration into crop fields and slow its spread,” said Emily Regnier of Ohio State University, a member of the research team. “Where the weed is already established in crop fields, it is critical that growers focus on diversification. They need to plant a more diverse combination of crop species, use more diverse tillage practices and reduce their reliance on herbicides with a single site of action.”
Giant ragweed has been a concern for crop growers for more than three decades. However, this is one of the first studies to produce quantitative data on how the ragweed spreads.