What is in this article?:
- An IPM approach to managing herbicide resistant ryegrass in Northeast Texas
- Crop rotation
- Plant certified seed
- Consider planting into a stale seedbed
- Plant an earlier maturing variety
- Chemical control: twostep herbicide program
- Annual losses from annual ryegrass in Northeast Texas run in the millions of dollars.
- Annual ryegrass populations (both resistant and susceptible) in cropland can be greatly reduced by using cultural and mechanical means in combination with chemical control techniques.
- For chemical control consider a two=step program.
TEXAS AGRILIFE Extension IPM specialist Jim Swart evaluates a wheat field for resistant annual ryegrass infestation.
Chemical control: twostep herbicide program
1. Spray Axiom at 6 ounces per acre when ryegrass is in the one- to two-leaf stage of ryegrass development. A good rule of thumb is to spray the wheat crop when you can “row” the wheat. Axiom has both pre-emergence and post-emergence activity, so you want to have the wheat plants emerged before spraying. However, Axiom is most effective on small ryegrass, so the sooner you can apply it after wheat emergence, the better.
2. Apply Axial XL at 16.4 ounces at the two-to-three tiller stage of ryegrass development. In Northeast Texas, this normally falls in early to mid-January.
The following varieties have shown good tolerance to the 6 ounce rate of Axiom. Wheat treated with Axiom produces slightly less early forage, but the plants recover by harvest and produce normal yields:
USG 3555, USG 3295, USG 3251, Syngenta Magnolia, Syngenta Coker 9553, Syngenta Oakes, Syngenta Jackpot, Terral TV 8525, Terral TV 8861, Terral TV 8558, Pioneer 25R30, Pioneer 25R40, and Pioneer 25R47.
All of these varieties appear to be safe choices to use with Axiom at 6 ounces. Terral LA 841 was also evaluated in these studies, but it does not appear to be as tolerant to Axiom as the others. Growers will likely still see some ryegrass plants survive this two-step treatment. However, the ryegrass “escapes” will be suppressed by the wheat crop, and are not visible until after the wheat is headed. Our research has shown these late emerging ryegrass plants are not competitive, and do not significantly reduce grain yields.