Conditions Determine When Weed Is Beneficial

PRINCETON, KY.
   A weed that also exhibits some benefits is under fire by Kentucky Weed Scientist Dr. Jim Martin, who spoke about its control at a recent meeting.
   “I’m here to talk about a weed that’s really not a brand new weed itself,” he said. “Italian ryegrass is often called an annual ryegrass because in this neck of the woods it tends to respond mostly as an annual. It’s a weedy plant but it has some benefits to it.”
   Italian ryegrass is a good plant for waterways when sowing it with fescue, because the seed is relatively inexpensive and it establishes itself relatively quickly.
   “However, as a weed scientist, I see it on the weedy side; it can be a problematic plant if it gets out of control,” Martin added. “We’ve seen some examples of resistance showing up in wheat, including resistance to ACCase inhibitors such as Axial XL and Hoelon or ALS inhibitors such as Osprey and Powerflex.”
 









 Dr. Jim Martin, Kentucky weed scientist 
 discusses the control and benefits 
 of the weed Italian ryegrass.
 Photo by John LaRose, Jr.












   The good news is the number of acres of Italian ryegrass in Kentucky is minimal compared to some states to the South. But it does exist here, and farmers are urged to be on the lookout for it because once it appears, it spreads quite rapidly in wheat.
   “Ryegrass is prone to developing or spreading herbicide resistance because it matures about the same time the wheat does; so when you’re harvesting wheat you’re going to spread it with the combine. That’s really just a prime situation for spreading resistance.
   “One of the newer cases of resistance that’s shown up this past year is Roundup or glyphosate resistant ryegrass in no-till corn,” he added. “A grower in Warren County had a corn field where multiple applications of glyphosate did not control ryegrass. Some of our preliminary tests in the greenhouse suggest this population is resistant to glyphosate. So we want to alert growers there are different types of herbicide resistant ryegrass that can occur in wheat as well as corn. Growers are encouraged to use a balanced herbicide program of multiple chemistries throughout the rotation system,” Martin summed. ∆
   BETTY VALLE GEGG-NAEGER: Senior Staff Writer, MidAmerica Farmer Grower