Search
As LSU AgCenter specialists work to expand the range of sugarcane production in Louisiana, they must address new challenges that growers may face.
Sugarcane growers that have previously produced cotton and grain in central Louisiana may be faced with weed issues less common with growers south of the Interstate 10.
Weed species can vary based on cropping systems, management practices and the environment, said Matt Foster, who became the AgCenter sugarcane weed specialist in 2023.
“Cotton and grain growers in Louisiana typically battle broadleaf weeds like glyphosate-resistant Palmer amaranth, but that species isn’t problematic in sugarcane production,” he said. “By transitioning to sugarcane, growers may slowly begin to face issues with grassy weeds like bermudagrass, itchgrass and vaseygrass.”
A research project in collaboration with the U.S. Department of Agriculture Agricultural Research Service investigating biodiversity in itchgrass throughout Louisiana is ongoing, he said.
Sugarcane and other row crops share some common weeds, such as Johnsongrass and Italian ryegrass. However, in some parishes outside the traditional sugarcane growing area, those weed species can be resistant to glyphosate herbicide, he said. In parishes where sugarcane has long been a common crop, Italian ryegrass resistance to paraquat, atrazine, metribuzin and diuron was recently documented.
“Herbicide-resistant weeds are a major problem in crop production and it’s important to proactively monitor their occurrence,” said Foster, who added that research investigating herbicide resistance in grassy weeds from fallow sugarcane fields is underway.
Weed management in sugarcane can be challenging due to its perennial growth and a lack of herbicide-resistant varieties. Sugarcane weed management programs rely heavily on preemergence herbicides that stop weeds from germinating or sprouting. Weed control is accomplished in both the fallow period and in-crop with tillage and herbicides combined with competition by shading from the crop.
“The fallow period is the foundation for weed management,” Foster said. “Typical weed control strategies in the fallow period include multiple tillage operations and multiple applications of glyphosate alone or in combination with other herbicides because you're limited in what herbicides you can use in the crop.”
