What is in this article?:
- 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.
The most effective management technique to control herbicide resistant annual ryegrass populations is crop rotation. Where resistant ryegrass is observed following a timely Axial XL application, the best option is to rotate that field to another crop for one or two years. The best rotation option appears to be corn, followed by grain sorghum, cotton, and soybeans. Sunflowers may be another option but more research needs to be done to ascertain the agronomic viability of sunflowers in this region.
Crop rotation enables growers to attack ryegrass populations from several angles. First, rotation to summer annual crops allows growers to reduce ryegrass populations that emerge over the fall and winter months with tillage and/or non -selective herbicides. In addition, introduction of other classes of herbicides into the rotation will further suppress any ryegrass “escapes” from the fall-winter management program.
Sometimes crop rotation is not a good option. Soils with the worst ryegrass infestations in the region are the Crockett and Wilson silt loams. The Crockett series consist of deep, moderately well-drained, loamy soils on uplands. They have slopes ranging from 1 to 5 percent. The Wilson series consists of deep, poorly drained soils. Wilsons are relatively flat, with slopes in the 0 to 1 percent range. Both of these soil types are often referred to as “grey land” soils and are best suited to grow wheat and cotton.
Grain sorghum has some problems with lodging when grown on these soils, but its drought tolerance would be advantageous. They are too droughty to produce dependable yields of corn and soybeans. Cotton is not a good short term option for most producers in the region as it requires specialized harvesting equipment. These considerations have made wheat the crop of choice for these grey land soils.