New data from Corteva Agriscience has shown that farmers can achieve excellent levels of control of volunteer oats in the autumn.
Unwanted oats are typically addressed in the spring, but if left unchecked for months, volunteers can impact subsequent crop yield.
Trials conducted over the past 12 months using Corteva’s Broadway Star herbicide show that where tame oats were treated in the autumn – while they small – almost 100% control was achieved.
The results from early and late-spring applications were a lot more variable, according to the company.
Volunteer oats
The global crop protection and seed company advises growers to check for volunteers in any fields where oats were harvested last year, and act this autumn where the need arises.
“Volunteer oats can be more difficult to manage than wild oats and there is a more limited choice of products available that effectively control them,” Corteva’s cereal herbicide product manager, Alister McRobbie said.
“Broadway Star is a contact herbicide that needs active weed growth for best results, so warm moist conditions are essential for optimum performance, and conditions are good for that at the moment.
The varieties Fusion; Elyann; Isabel; Balado; Mascani; Lineout; Southwark; Canyon; and Dalguise were used in the research work.
In all cases, Broadway Star achieved near 100% control when applied with an adjuvant in the autumn when volunteers were smaller, according to the trials.
Early spring and late spring applications were far more inconsistent and did not always control all oat varieties trialled.
“Timing trials have also suggested best results occur when soil temperatures are 8°C or above at a 10cm depth,” McRobbie added.
Spraying
According to Corteva, spray quality should be fine, or the finer side of the medium spectrum.
“We recommend a conventional flat-fan nozzle at 130-150L/ha water volume to provide the best combination of droplet size and coverage,” McRobbie continued.
“But growers can go down to 100L/ha providing the crop or weed density is not too great.”
Air induction or low drift nozzles are not recommended and adding an adjuvant such as Abacus, Activator 90, Drill, Kinetic or Torpedo is critical to performance.
Regarding the more general use of herbicides, Teagasc is reporting that populations of blackgrass and Italian ryegrass are resistant to the post-emergence ALS herbicides – Pacifica and Broadway Star.
Reduced sensitivity has been detected in brome species to Pacifica. However, brome is still well controlled by Broadway Star.
In addition, Teagasc is confirming that a resistant population of annual meadow grass to Pacifica has been detected in Ireland, while Broadway Star does not control annual meadow grass.