Plant diseases threaten UK whisky and gin

In an article to mark UK Plant Health Week, three leading researchers warn about an invasive pathogen called Phytophthora austrocedri currently spreading through juniper trees in Scotland. Gin is usually derived from juniper berries, and Scotland produces 70% the UK’s gin.

The scientists also warn that a fungal disease called Ramularia – which affects the barley used to make Scotch whisky – has slowly grown in severity over the last decade.

The article is written by Professor Fiona Burnett from Scotland’s Rural College (SRUC), Professor Sarah Gurr from the University of Exeter and Dr Sarah Green from Forest Research – all affiliated to Scotland's Plant Health Centre.

Scotland's whisky exports are worth £4.9 billion annually – accounting for a massive 75% of Scottish food and drink exports and 21% of all UK food and drink exports.

Gin is fast gaining ground on whisky as the drink of choice, with total global sales worth £3.2 billion in 2019.

Professor Gurr said: "At a time of heightened awareness of the impact of epidemics on human health, we must also remember that disease has a huge impact upon plant health.

"Food security and crop protection rely heavily on breeding for disease resistance and upon the widespread spraying of fungicides and insecticides.

"However, despite such disease protection strategies, we still lose around 20% of our crops to disease.

"We hope Plant Health Week will raise awareness that disease devastates not only human life but also crops."

The P. austrocedri pathogen entered Britain through the plant trade and may have got into juniper woodlands through well-intentioned planting schemes.

It lives in the soil and spreads in both soil and water, infecting juniper roots and killing large numbers of juniper trees, especially on wet sites.

Although gin can be produced from spirits derived from a wider choice of grains or even potatoes, it relies on juniper berries for its traditional and distinctive flavour.

Luckily for gin drinkers, researchers in Scotland have found that some junipers are resistant to P. austrocedri and it is hoped that natural regeneration will allow juniper populations to recover over time.

Science is also helping to identify juniper sites that are less vulnerable to the pathogen and which can be targeted for conservation and protection.

Members of the public can take simple steps to help protect the gin industry – and stop the spread of plant pathogens in general.

These include cleaning soil from boots, bike tyres and dog paws before and after visiting forests, moors and woodlands to prevent disease spreading to new sites.

Professor Burnett said: “International Plant Health Week is a chance to flag that everyone can play their part in protecting Scotland’s plant health assets.

"Whisky is equally at risk to gin through barley diseases which slash crop yields.

"But the principles of best plant health practice such as sourcing seed and plants with care and avoiding moving problems inadvertently in soil apply equally to field crops and the plants in our moorlands, gardens, forests and fields.”

Scotch whisky depends on healthy barley crops with big grains that malt well and produce high levels of alcohol ready for Scotland’s many distilleries.

Crops affected by Ramularia produce shrivelled grains which are often rejected before they even enter the malting process.

Ramularia operates by stealth and can evade the barley plant’s normal defence mechanisms.

New mutants of this pathogen have developed resistance to fungicides, so the risk to the 2020 barley crop is greater than ever.

Scotland’s Plant Health Centre was launched in 2018 and is funded by the Scottish Government through its Rural and Environment Science and Analytical Services Division.

It brings the plant sectors for forestry, horticulture, environment and agriculture together to co-ordinate plant health knowledge, skills, needs and activities across Scotland.

The centre directorate is headed up by the James Hutton Institute, and has sector leads from Scotland’s Rural College (agriculture), Royal Botanic Garden Edinburgh (horticulture and environment) and Forest Research (forestry).

Read the blog here: https://www.planthealthcentre.scot/blog