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.
Plant an earlier maturing variety
Late maturing varieties are generally developed in more northern climates, and their progression is determined more by day length than temperature. This “safety mechanism” prevents the plants from jointing too early in mild winters and succumbing to a late freeze in the spring. These varieties spread by tillering in the fall and early winter but do not produce much early forage. They are designed to spend more of their life span in colder weather and often under snow cover.
In contrast, earlier maturing varieties are developed in southern breeding programs and their development is often controlled more by temperature than day length. They generally produce more fall and early winter forage, which is desired by livestock producers. It is this same early forage characteristic that makes these varieties attractive in a resistant ryegrass management program.
We experienced an herbicide failure with Axial XL in our variety study near Royse City this year, and it compromised our yield data. However, we were able to measure the competitive advantage that these early varieties have in a resistant ryegrass management program.
Terral 8861 and Pioneer 25R40 were among the highest yielding wheat varieties in our other trials this year. However, their slower growth characteristics in the fall and early winter allowed the ryegrass plants a competitive edge in this study. In contrast, the three earlier maturing varieties here (USG 3555, Coker 9553, and Magnolia) produced more early forage, which smothered the ryegrass seedlings. This allowed them to produce higher yields.