Professor Ian Toth: New centre tackles growing threat of pests to Scotland’s plants

Professor Ian Toth, a senior scientist at the James Hutton Institute, is Director of Scotland's Plant Health Centre.
Professor Ian Toth, a senior scientist at the James Hutton Institute, is Director of Scotland's Plant Health Centre.
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Plants are a wonderful part of our beautiful landscapes and biodiversity but they are also essential to the economies of tourism, farming and rural industries in Scotland.

However, plants are constantly under threat from pests and diseases. Many of these are already here and we do our best to manage them but other, potentially far more damaging invasive ones, are lurking ready to strike.

A new government-funded Plant Health Centre of Expertise, which pulls together specialists from nine institutions, has been launched to support Scotland in dealing with these many threats, to protect our plants wherever they are, including wild spaces, forests, gardens, amenity parklands and agricultural land. Scotland has a unique and special environment and so plant health threats and solutions need careful consideration. Many will remember the terrible scenes in the 1970s when Dutch elm disease destroyed tens of thousands of elm trees in Britain.

Central and southern England were particularly hard hit while Scotland escaped relatively unscathed. Was this just luck or did the fungus and its insect vector, the bark beetle, fail to reach Scotland?

Actually, neither is true. What seems to have happened is that the more predominant species of elm tree in Scotland (wych elm) was, and still is, less appetising to the bark beetle than the English and smooth-leaved elms in the south, so the beetle was less likely to feed on these trees and spread the fungus.

Also, our cooler climate almost certainly made a difference to beetle populations, while a competing ­fungus present in Scotland may have acted as a natural control agent against the beetle. What might ­surprise you is that the disease is still present and spreading in Scotland but is being actively and effectively managed.

In recent years, outbreaks of Phytophthora ramorum on larch and of dieback on native ash remind us that freedom from tree diseases can never be taken for granted.

Plants in many settings are at risk. So much so that in Scotland, as elsewhere in Europe, 15-20 per cent of our crops are lost to pests and diseases annually, amounting to almost a million lost tonnes of production valued at £200 million per year.

These losses inevitably mean higher prices in supermarkets, challenging times for businesses, disappointment for gardeners and a knock effect to the economy.

However, many more pests continue to threaten our borders. The UK Plant Health Risk Register ­currently has 977 potential threats on its list including Xylella fastidiosa, Zebra chip, the longhorn beetle and the beautiful but deadly bronze birch borer. Keeping such organisms out and developing strategies to deal with them if they do arrive will be important topics for the new centre.

Scotland avoided the worst of Dutch elm disease because we were fortunate to have been different enough to the south to escape its effects. ­However, what if such differences made Scotland more rather than less vulnerable to other threats in the future?

Our cooler, wetter climate will be more attractive to some pests, and Scotland’s unique landscape may contain some particular vulnerabilities – for example, in the concentration and importance of conifers (including the iconic Scots pine) and birch trees in our forests, as well as the valuable seed potato, soft fruit and barley sectors.

All these plants make important contributions to our landscapes whether as places of production, international environmental importance or settings for tourism and recreation. Plants have also been closely linked to better mental health, with wild spaces, nurseries, gardens, parks, amenity sports grounds and allotments having much to offer to our health and wellbeing.

The new Plant Health Centre will focus on the distinctive needs of Scotland, supporting its plant health needs and increasing the resilience of its plant-based industries and the people who depend on them.

By pulling together an interdisciplinary team of experts across ­different plant sectors (including forestry, agricultural, horticulture and the environment) and working together with the recently appointed Chief Plant Health Officer for Scotland, the centre will form a unique capability, allowing it to respond rapidly to ­government and other agency enquiries and offer advice and support on current and new invasive pests. For more information visit www.planthealthcentre.scot, email info@planthealthcentre.scot or follow PHC on Twitter @PlantHealthScot.

Professor Ian Toth, a senior ­scientist at the James Hutton Institute, is director of Scotland’s Plant Health Centre.