chemical resistant ryegrass

Ryegrass is one of the main problem-causing weed species found in many farmers' fields, not only in America but all across the world. Many studies I have come across have taken place in other regions such as Australia and the UK. However, this is also a problem in the fields right next to my home in North Carolina. Ryegrass is consistently beginning to grow more resistant to chemical herbicides. Non-target site resistance is the main type of resistance happening in ryegrass. This basically means that the weed is insusceptible to herbicides. Traits that make the depletion of ryegrass more difficult consist of its fast germination rates and seed production. Although there are said fixes, the chemicals that “solve this problem” are temporary. 

I spoke with local farmer (and my dad) Matt Stegall and here is a more direct view of how this is affecting his crops. “In our wheat harvest this ryegrass is a major problem because it chokes out the wheat and greatly reduces the wheat yield. Rye grass seed can make its way into the grain samples which reduces wheat quality and test weight. Complications also arise when we are trying to burn down before we plant corn. The chemicals we use will not kill the ryegrass and it keeps growing, robbing the land of nutrients and moisture that the corn has to have to produce grain.” From this I gathered that the ryegrass has negative impacts through various crop seasons and doesn’t target just one crop. 

In order for ryegrass to best be managed some suggested tactics are as follows; varied crop rotation, deep plowing and clean equipment. This all helps to subdue ryegrass seed germination and spreading. Some ryegrass populations are not resistant to all herbicides. Glyphosate seems to be continually overthrown, but fortunately “among the remaining herbicides, glufosinate, rimsulfuron and sethoxydim were found to deliver the best postemergence control.” This weed is challenging farmers and researchers to deliver a permanent solution.

“Italian Ryegrass Resistance to Herbicides.” ANR Blogs, ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=28788. Accessed 02 Feb. 2024.

“The Growing Challenge of Herbicide Resistant Italian Rye-Grass.” AHDB, 18 Aug. 2022, ahdb.org.uk/news/the-growing-challenge-of-herbicide-resistant-italian-rye-grass#:~:text=The%20majority%20of%20resistance%20in,(detoxify)%20crop%20protection%20agents. Accessed 02 Feb. 2024.