An aggressive fungus could wipe out a quarter of British wheat crops this harvest season, scientists have warned.

The virulent ‘Warrior’ strain of yellow rust has been found in many crops in the UK and experts warn it could present a serious threat to wheat production.

The National Farmers Union warned that around a quarter of British crops could be affected and said that European pesticide bans were making it more difficult to control.

Yellow Rust can cause significant reductions in quality and yield, and in some cases, lead to the loss of the entire harvest.

Farmers have been urged to spray crops thoroughly but scientists say they are unsure if regular fungicides will be affective against the new strain. Many more powerful chemicals have been banned by Europe.

Guy Gagen, Chief Arable Advisor at the NFU, said: “Naturally farmers and the NFU are concerned about new strains of disease adaptation to UK conditions.

“Yellow rusts are more prevalent in the East of the country and can impact yields significantly, up to 25 per cent for individual crops when conditions are right. But this is potentially even more serious.

“If one quarter of the crop grows then that is very serious for farmers and they may not be able to make a profit.”

The new fungus strain has adapted to warmer temperatures and overcome many of the major defensive genes in wheat. It appears to have come from abroad and could have travelled in the air or attached to clothing, experts believe.

Researchers from the John Innes Centre, The Sainsbury Laboratory, The Genome Analysis Centre and the National Institute of Agricultural Botany sequenced genetic material from 39 infected samples of wheat collected from 17 UK counties.

Of the samples, 11 were genetically similar to a strain called “Warrior” strain which emerged in 2011 as a serious threat to European wheat production.

The samples showed that the fungus had enhanced its ability to overcome disease resistance in wheat.

Lead author Diane Saunders of the John Innes Centre and The Genome Analysis Centre (TGAC), UK, said: “Our research shows that in the UK we have a newly emerging population of wheat rust fungus that could be the result of an influx of more exotic and aggressive strains that are displacing the previous population.

“Yellow rust is always a serious problem and this is a more virulent strain. We don’t really know how things will pan out, but it’s in every area that we grow wheat.

“ We don’t know until the summer if it has taken hold and how far fungicides have worked.”

Source - http://www.telegraph.co.uk/