Researchers are hunting for ALS-resistant broad-leaved weed populations and growers are asked to get in touch if resistance is suspected on their farm.

Acetolactate synthase (ALS) inhibiting herbicides are fundamental to most broad-leaved weed control strategies in UK cereals.

However, the ALS-inhibiting herbicide class has the greatest incidence of weed resistance worldwide and resistance to this class is already common in broad-leaved weeds (BLWs) in European countries, such as Italy and Spain.

In the UK, reliance on ALS herbicides has led to the development of ALS-resistant black-grass and it could also have been inadvertently leading to a build-up of ALS resistance in BLWs.

Already a significant issue in parts of Europe, ALS-resistant poppy, chickweed and mayweed populations have now been identified at multiple locations in the UK.

To improve understanding of the extent of resistance spread in BLWs across the UK, HGCA-funded researchers at ADAS are asking growers who suspect their farm is harbouring resistant poppy, chickweed or mayweed populations to get in touch.

ADAS researcher Lynn Tatnell said: “Lessons learnt from black-grass resistance in the UK show that it is essential to be proactive to help prevent or slow the development of widespread resistance in BLWs.

“During July, we are looking to collect seed from broad-leaved weeds suspected of being resistant to help us get to grips with the extent of the problem in the UK and assist with the development of practical resistance management guidelines to retain herbicide efficacy.”

Growers who believe they have issues with resistance in poppy, chickweed or mayweed are asked to contact lynn.tatnell@adas.co.uk