What is in this article?:
- To an increasing number of Southwest wheat growers, herbicide resistant ryegrass poses an equally disturbing dilemma.
- Once-effective herbicides have failed to control some ryegrass in wheat stands.
- The best solution so far is what IPM agent Jim Swart calls a “two-step program.”
WHEAT INDUSTRY OBSERVERS, including farmers, crop protection company representatives, Extension agents and others, gathered at field plots near Fairlie, Texas, to view herbicide and resistant ryegrass trials.
The best solution so far is what Swart calls a “two-step program,” a resistant ryegrass management system that keeps Axial XL in play. The program calls for application of Axiom, a Bayer CropScience herbicide, at 6 ounces per acre when you can “row your wheat. We don’t want to apply until wheat is up to stand, as Axiom has some preemergence activity,” Swart said. Following that, Axial XL is applied at 16.4 ounces per acre at the two-leaf stage of ryegrass, usually in early to mid January. “We add a half-ounce of Amber with Axial XL to control broadleaf weeds,” he said.
That combination has taken out the resistant ryegrass. “And it keeps Axial XL available,” Swart said. “Axial XL has been doing a good job and is still doing a good job in many places.” He said using Axial XL in combination with Axiom allows farmers to keep a good herbicide available when ryegrass becomes resistant. “We really have nothing to replace Axial XL,” Swart said.
He’s looked at Axiom for about 12 years but until recently could find no real fit because “Axial XL was doing such a good job. Now, we can apply Axiom early and come back with Axial XL and take out resistant ryegrass.”
Swart said a commercial field near the test plots failed last year and was overrun with resistant ryegrass. “They used the two-step program this year and will make a good wheat crop. This program is going to buy us a lot of time.”
Gary Schwarzlose, Bayer CropScience tech service representative, said Axiom also has some broadleaf activity, mostly on mustards and henbit.
Swart and other industry representatives cautioned farmers to be alert to potential resistant ryegrass infestations and to watch for “slippage” of current herbicide programs.
“Pay attention when you combine wheat,” Swart said. “If you see ryegrass at harvest following anAxial XL application, it may be resistant. And you can scatter seed all over the field with the combine.”
Russell Sutton, Texas AgriLife research agronomist, said ryegrass seed spreads easily. “We can spread it with a combine, other farm equipment” or through natural means — wind, birds, etc.