A 'FORGOTTEN' disease pathogen could pose a threat to UK crops if it is not closely monitored, experts warned this week.

The re-emergence of stem rust has prompted a warning that scientists, breeders, farmers and conservation groups must continue to work in close collaboration to prepare for the potential re-emergence of this old disease.

Work between groups has already started following the discovery of a single wheat plant infected with stem rust – the first confirmed case of the plant disease in the UK in more than 60 years. Stem rust of wheat and barley has, throughout history, been associated with crop failure and famine, and recently re-emerged in western Europe.

Following the discovery of a single infected wheat plant in Suffolk in 2013, Dr Diane Saunders and Dr Brande Wulff, from the John Innes Centre, in Norwich, led a global team of collaborators to carry out genetic tests that compared this strain to the dominant global populations of the pathogen.

Their results showed that the UK strain belongs to the digalu race of the fungus, which was responsible for a devastating outbreak of stem rust in Ethiopia in 2013, and smaller outbreaks in Sweden, Denmark, and Germany in the same year.

Further investigations carried out by Dr Jane Thomas, at NIAB, in Cambridge, found that more than 80% of UK wheat varieties tested would be susceptible to the UK strain of this pathogen – meaning that if the strain became established in the UK, a large proportion of UK wheat could be at risk.

The research team also warned that a perfect storm of conditions favourable to stem rust resurgence is happening at the moment across Europe.

Dr Daniel Bebber, of Exeter University, said that climate change during the past 25 years suggested ideal conditions for fungal pathogen growth and infection.

In addition to the lack of resistance in European wheat varieties, in recent years the alternate host of the pathogen, barberry (berberis vulgaris), has also been increasing in popularity. This hedgerow shrub plays a key role in the life cycle of several rust pathogens, including wheat stem rust.

The barberry shrub was largely removed across England up until the early part of the 20th century, as farmers noticed that cereal crops grown adjacent to it were at greater risk of stem rust. However, over the last 10 years or so Barberry shrubs have been planted in efforts to conserve the barberry carpet moth, an endangered species.

The next steps in the process, said Dr Saunders, was to carry out a study to map and sample barberry across the UK. “Replanting barberry in woodlands, gardens and areas away from arable land would ensure we provide vital habitat for the endangered moth, whilst limiting its potential impact on enhancing rust pathogen diversity,” he said.