05 June 2025

Walk crops for grass weed issues

Teagasc Crops Specialist, Shay Phelan shares key tips and advice for controlling grass weeds, and encourages growers to walk all crops over the coming weeks to identify any potential issues.

Over the last number of weeks, we have heard of cases of blackgrass and Italian ryegrass appearing on tillage farms.

On one hand, this is worrying. On the other hand, however, it means that growers are starting to become more aware of the risks that these two grass weeds pose on tillage farms.

Unfortunately, as you are probably aware, this year in Oak Park we have confirmed that there is a population of Italian ryegrass which is resistant to glyphosate present in Ireland. Similar reports have been confirmed in the UK and Italy.

This poses a very difficult problem for the famers involved as the so called ‘nuclear option’ to desiccate the affected areas of the crop, as we would have seen across the UK, is now not an option in the affected fields. Cultural control methods are the main solution in these fields and ensuring no seed is returned to the soil is critical, so rogueing, stubble cultivations etc. must be employed as part of the control programme.

Figure 1: Irish growers are now desiccating crops infected with blackgrass

For most growers who have blackgrass or Italian ryegrass on their farms, chemical desiccation will still be a viable option, even though for the 2025 crop this will be a difficult pill to swallow. Figures from the UK show that many farmers are spending over £150 sterling per acre per annum on herbicides to control the problem. From these figures, it is clear that this is not sustainable, so a full suite of IPM measures including rogueing and preventing seed return are the only way to control the problem.

Over the coming weeks growers need to walk all their crops and identify any potential grass weed issues and then draw up a control programme. Where necessary, this may include desiccation which will not only prevent the spread on your farm but also onto other farms. Research from the UK showed that blackgrass spread along the roadway network from loads of straw being transported from tillage farms to livestock farms.

For more tips and advice on controlling grass weeds, visit here.