Ryegrass, Italian

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Italian ryegrass is an annual or biennial ryegrass that has become a problematic herbicide resistant weed in several states. It is considered a high concern herbicide resistant weed in Mississippi. While it is not native to the US, it is present in every US state. Some varieties of Italian ryegrass are sometimes planted as a companion crop for alfalfa, or in other seed mixes. See resources below for herbicide recommendations. Integrated weed management recommendations include:

  • Prevent entry by ensuring that all feed, seed, and equipment entering the property are free of ryegrass seed
  • Do not allow patches of Italian ryegrass to grow along ditches, fence lines, or other border areas; control them before they spread to the fields
  • Vary the effective herbicide sites of action (at least two) in tank mixes and change them up between seasons to decrease the chance of selecting for resistant populations

Herbicide Resistant Populations:

  • Group 1 (ACCase inhibitors)
  • Group 2 (ALS)
  • Group 1 + 2
  • Group 9 (glyphosate)

Locations of resistant populations:

Arkansas, California, Delaware, Georgia, Idaho, Kentucky, Louisiana, Maryland, Mississippi, Missouri, North Carolina, Oregon, South Carolina, Tennessee, Virginia (Search by State to see which resistant populations are present in each state)

Resources:

In the News: Control Italian Ryegrass at First Opportunity – Delta Farm Press

Webinar (23 minutes): Management of Glyphosate Resistant Italian Ryegrass – Jason Bond, Mississippi State

USDA Plant Profile for Italian Ryegrass

Photo Gallery of Italian Ryegrass – University of California

Italian Ryegrass Management in Soybeans – Purdue University

Glyphosate-Resistant Italian Ryegrass Management Tips – Jason Bond, Mississippi State University

Italian Ryegrass in Wheat and Small Grains – Washington State University