By Blake Jackson
Italian ryegrass continues to create problems in Kentucky no-till corn fields, with growers reporting increasing numbers of escapes despite earlier herbicide programs.
According to Dr. Travis Legleiter, weed specialist with the University of Kentucky Extension Service, many fields showed good control following fall and spring burndown applications, yet patches of surviving ryegrass remain common. In some cases, infestations have become severe enough to threaten crop performance.
The challenge becomes more difficult once corn has emerged and ryegrass plants have reached advanced growth stages. At that point, post-emergence herbicide options are limited, making it critical for growers to know which herbicide tolerance traits are present in their corn hybrids before choosing a treatment strategy.
Research conducted in 2022 at the University of Kentucky Research and Education Center evaluated ryegrass escapes ranging from 12 to 52 inches tall, with plants averaging about 31 inches in height. Results showed that for conventional corn hybrids, nicosulfuron-based products remain one of the few available management options.
Adding rimsulfuron or HPPD inhibitors such as tolpyralate provided only slight improvements in performance. Researchers emphasized that growers should expect suppression rather than complete control in these situations. Recommended treatments included Steadfast Q or Katagon.
For Roundup Ready and Liberty Link corn hybrids, glufosinate products performed more effectively on larger ryegrass plants. Applications of Liberty Ultra or generic glufosinate products such as Interline, Cheetah, Forfeit, or Surmise offered stronger suppression.
Additional tank-mix partners including Accent Q, Steadfast Q, Impact, and Shieldex may provide added herbicide activity, although results varied depending on plant size and field conditions.
Photo Credit: travis-legleiter
Categories: Kentucky, Crops, Corn