Potatoes could be off the menu as crop pests threaten UK

Report warns that if they continue to spread at their current rate, the world’s biggest food-producing countries will be 'saturated'

Fungi pose the biggest threat globally and in the UK, where they threaten the country’s wheat and potato harvests (Getty Images)

Britain has “significantly underestimated” the risk that crop pests pose to its food supply. Fungi and viruses present so great a danger to staples such as wheat and potatoes that they may force the nation to change its diet, an academic has warned.

The rise of deadly pests poses a threat to the world’s entire food system, but the UK is among the most vulnerable countries, according to a new study from the University of Exeter. It forecasts that food-growing nations, including the UK, will be “overwhelmed” by pests within the next 30 years as climate change, inadequate biosecurity measures and new variants help them spread.

“The UK has significantly underestimated the scale of the threat. This is a huge problem that is lacking in public and political awareness. People are absolutely paralysed with fear of diseases like Ebola, but while they are extremely dangerous, the need to tackle crop diseases is just as pressing,” said Professor Sarah Gurr, of the University of Exeter and Rothamsted Research.

“We are not spending enough on research, on training, on surveillance and on biosecurity. Unless we significantly step up our efforts we could be forced to change our diets in the future as crops come and go,” she added.

Crop pests include fungi, bacteria, viruses, insects, nematodes (worms) and viroids (plant viruses).

Fungi pose the biggest threat globally and in the UK, where they threaten the country’s wheat and potato harvests.

Zymoseptoria tritici – or Septoria leaf blotch – and Blumeria graminis, a powdery mildew, are a danger to wheat, while the potato cyst nematode and new variants of Phytophthora infestans threaten the potato.

The report warns that if crop pests continue to spread at their current rate a significant portion of the world’s biggest food-producing countries will be “saturated” with pests – the crops simply wouldn’t be able to accommodate any more.

The UK, the US, Germany, Italy, France, Japan, India and China are all on course to be fully-saturated – or inundated – with pests by the middle of the century, the report predicts. Dr Dan Bebber, of the University of Exeter, who also worked on the report, warned this would pose a “grave threat to global food security”.

More than one in 10 pest types is already present in about half the crop-growing countries, but that level is set to increase dramatically, the report states.

The study looked at the current “distributions” of 1,901 crop pests and pathogens, and historical observations of a further 424 species. It also made significant use of historical records at the CABI agricultural research institute, which document crop pests and diseases around the world and date back to 1822.

Dr Timothy Holmes, CABI’s head of technical solutions, said: “By unlocking the potential to understand the distribution of crop pests and diseases, we’re moving one step closer to protecting our ability to feed a growing population. The hope is to turn the data into positive action.”

The report’s authors say their findings support the view of previous studies that climate change is likely to significantly affect pest pressure on agriculture, with the warming Earth having a clear influence on the distribution of crop pests. Fungi is moving seven kilometres northwards each year.

A spokesman for the Department for Environment, Food and Rural Affairs, said: “We take the issue of plant biosecurity very seriously and have appointed a chief plant health officer to oversee our work. This includes a plant health risk register and biosecurity strategy for the UK.”

The chief plant health officer is Professor Nicola Spence, who previously headed a consortium of York Council, the University of York and York St John University, set up to develop the local economy.

Bug patrol: Major threats

Septoria leaf blotch: Probably the biggest threat to British wheat. The fungus already decimates between 10 per cent and 30 per cent of the UK wheat crop.

Blumeria graminis: This fungus causes a powdery mildew on wheat and other cereals. It is already present in the UK but expected to spread dramatically.

Potato cyst nematode: These roundworms live on the roots of potatoes and tomatoes and their larvae infect the roots.

Citrus tristeza virus: Although not a problem in the UK, where citrus plants such as oranges and lemons are not grown, this virus – meaning “sadness” in Portuguese – has reached at least 105 countries.