Weedy rice is a close relative of cultivated rice that infests rice fields worldwide and drastically reduces yields.
Weedy rice is a close relative of cultivated rice that infests rice fields worldwide and drastically reduces yields. To combat this agricultural pest, rice growers in the southeastern United States have been planting rice cultivars that were tweaked to allow them to apply herbicides that target weedy rice without harming the crop.
But only a handful of years after the introduction of herbicide-resistant rice in the early 2000s, Arkansas farmers started reporting that weeds in their fields were becoming herbicide-resistant, too. Laboratory analysis verified these accounts: Scientists saw evidence that the weeds were breeding with the crop rice, and that subsequent generations of hybrid weeds had some level of genetic resistance to herbicide.
Now a new study from Washington University in St. Louis shows that more than half of the weedy rice sampled in the rice-growing region of the southeastern U.S. has become herbicide resistant.
WashU scientists found that 57% of 201 samples of weedy rice collected from fields in nine counties or parishes of Missouri, Arkansas and Louisiana in 2022 were resistant to the imidazolinone (IMI) family of herbicides. In addition, 3.5% of samples were resistant to another newer class of herbicides that has only been used in southeastern U.S. rice fields since 2018.
Read more at Washington University in St. Louis
