‘Killer fungus’ found in UK – here’s why it’s not a bad thing

A new ‘killer fungus’ has arrived the UK – but we’re not at risk of turning into zombies just yet.

Instead, the new arrival has raised scientists’ hopes for restoring our natural habitats.

The so-called moss die-back fungus kills a type of moss that is damaging the environment at an alarming rate. 

The fungus infects the heath-star moss, itself an invasive species, that takes over and kills other plants.

It was discovered by Dr George Greiff, a scientist at the John Innes center in Norwich,

Greiff, who was working at the Amgueddfa Cymru museum in Wales when he discovered it, told the BBC that it could be a ‘rare example of the British environment fighting back.’

The heath-star moss is one of the most aggressive plant species in the country, found on rugged hillsides, garden fences and many things in between. 

‘I’ve even seen it growing in tarmac,’ said Greiff. ‘It’s caused a lot of problems.’

Scientists think the heath-star moss arrived here in the mid-20th century, and by the 1990s it was all over the place. 

It sends its spores more widely than other species and reproduces faster, meaning it has taken over quickly. 

In some heathlands across the country, some native mosses have even gone ‘locally extinct’, Greiff said.

But the new fungus causes ‘patches of death’ in the previously unstoppable invader, meaning that it could be a welcome arrival.

The moss die-back species is a close relative of the ash die-back fungus that has killed as many as 80 million ash trees in the UK, the scientist has worked out.

While that sounds like something threatening, Greiff reckons it only affects the heath-star moss, though his findings are not yet confirmed.

‘Some people might try to collect this moss to try and get rid of it, but it’s not very effective. It would be very resource-intensive, very expensive,’ he said.

‘To have a natural biological control agent doing it for us is really valuable.’

‘It’s exciting in so many respects. Though I am the only one looking for the fungus. It would be nice if some other people did too,’ he added.

The fungus works by growing both inside and on the surface of the moss, killing it from within, according to a 2025 study by Greiff. 

It spreads through infected patches in distinctive circular patterns, creating the brown rings of dead moss that he has been tracking across England and Wales.

It was formally identified as a new species only at the end of last year, after years of DNA analysis, the study added. 

Scientists in the UK and France had independently found it and only realised they were looking at the same fungus after comparing notes online.

The fungus appears most active in winter, when white powdery clusters appear on the tips of dying moss. These are the first visible sign that it is at work.

So far it has been found at more than a dozen sites across England, as well as in France, Belgium and the Netherlands, suggesting it is already more widespread than previously thought.

‘This fungus gives an opportunity to save these unique moss landscapes that are homes for insects, fungi, molluscs, other plants,’ added Dr Nathan Smith, who also works at the museum in Wales.

‘It gives a real chance to preserve and present their uniqueness and beauty,’ he told the BBC.