The new grass-weed threat to min-till

Once normally found on waste ground, roadsides and urban areas, the annual grass-weed rat’s tail fescue has been increasing in prevalence in recent years, creeping its way into arable fields.

The weed is already posing problems in France, Switzerland, Spain and Denmark – and is now starting to take hold in England and Wales, researchers say.

Although little information on its effect on crop yields is available, rat’s tail fescue is predominantly a threat in no-till winter cereals, where it can rapidly form dense carpets and compete with the crop.

A team of researchers from the University of Greenwich and Rothamsted Research has launched a nationwide survey to better understand the current knowledge and distribution of the species in the UK and its association with cropping practices.

Project lead Dr Lucie Buchi, from the Natural Resources Institute at the University of Greenwich, first discovered the weed while working on min-till and cover crop trials in Switzerland.

After speaking to colleagues in France and Spain, it became apparent the weed was becoming more prevalent across Europe, yet there was little information or advice available, says Dr Buchi.

“We want to find out the extent of the problem and whether it’s actually a threat, or transiently appearing in the field and then disappearing again.”

Judging by early responses to the survey, rat’s tail fescue has been present in arable systems for around 10 years but has been largely overlooked with more problematic weeds such as black-grass taking the limelight.

Dr Buchi says: “We think it’s growing prevalence is mainly linked to the reduction in tillage because it’s quite well controlled by ploughing – that would be our main explanation.

However, we’d like to investigate the climate aspect because it originates from the Mediterranean, so is quite adapted to dry conditions.

One question is if it’s spreading due to a change in climate.”

This is because its abundance has also increased in the wild, which cannot be linked to cropping practices such as reduced cultivations, she adds.

“Before starting the survey, we also thought it was more prevalent in the south of England, but from the responses we’ve received from farmers and agronomists, it seems to be a problem in the North East too and is more widely distributed than we first thought.”

In its natural habitat, rat’s tail fescue prefers light, sandy soils,