Herbicide resistant strains of wild oats found in Ireland

Anyone who grew up on or had a close connection to a tillage farm, may have spent many an evening pulling wild oats.

At yesterday’s Crops and Cultivation open day in Oakpark, Teagasc’s Ronan Byrne gave farmers an update on the wild oats situation on Irish farms.

Part of Byrne’s area of study involves understanding the issue of herbicide resistance in grass weeds, including resistance in wild oats.

“Last summer, we collected samples from 76 sites across Ireland and tested them for resistance to a number of different herbicide active ingredients,” the Teagasc Walsh Fellow said.

“The herbicides were split into two main crops. These were graminicides and sulfonylureas. The big finding from our research so far is that we do have resistant wild oats in the country.

“This is something we may not have thought was an issue this time last year, but we do have an issue now and it’s going to be more of a problem in continuous spring barley ground.

“Obviously, we are going to have a massive issue with black grass going forward. We do have resistant black grass. We have seen resistance in one or more actives in all of the black grass samples.

“But, something that is interesting in wild oats is that some plants are only resistant to one active ingredient and are totally susceptible to other active ingredients used in herbicides.

“That may form your management strategy going forward. You might be able to tailor your rotation in such a way that you grow crops, spray some of these active ingredients and get a good kill on your wild oats,” he added.

Key steps to identifying resistance on your farm:
  • Was spraying carried out in the correct weather conditions?
  • Was the herbicide applied at the correct rate?
  • Has a good coverage of all of the tillers been achieved?
  • Are live, uncontrolled plants present in proximity to dead ones?