An Italian ryegrass plant in the UK has been found to be resistant to glyphosate at the label rate. Research by ADAS and NIAB identified a single field population of Italian ryegrass which was resistant to glyphosate at the field label rate.

The researchers have said that it is the first documented case in the UK and the plant was located in Kent. They also explained that the weed population was in a high-risk scenario as large weeds were being controlled before planting a spring crop.

Glyphosate resistance has been found in 60 species in 30 countries according to ADAS.

Glyphosate effectiveness on Italian ryegrass in Teagasc trials.

In Ireland, Teagasc research has shown that generic glyphosate products can differ in efficacy and some need more product to work effectively. For example, to control Italian ryegrass 1,080g/ha (3L/ha of 360g/L glyphosate) were needed of one generic product compared to 720g/ha of another generic product or of a Roundup product.

Italian ryegrass has become a serious problem on tillage farms in Ireland since the crop was planted on tillage land after the drought of 2018 to provide forage to livestock.