A new science centre of expertise has been set up to tackle threats to plant life in Scotland – but why do we need it?
The Scottish Government-funded Plant Health Centre of Expertise, which pulls together plant health specialists from ten institutions, has been launched to support Scotland in dealing with the many threats to its plant life across plant sectors including forestry, horticulture, environment and agriculture.
In Scotland, as in the rest of Europe, we lose 15-20% of our crops to pests and diseases even though we have some of the most advanced agricultural systems anywhere in the world.
Plants are often seen but largely go unnoticed as we go about our daily lives, yet plants are essential to us and to most if not all other life around us. They are essential for regulating our climate, the air we breathe, the food we eat, the furniture and houses we build, and our social wellbeing as we tend the flowers in our garden or walk in the hills. While we might often take plants for granted, there are lots of other organisms that do not, including those that live, breed and feed on them. Many of these organisms are harmless and some play essential roles in promoting plant life, for example the bumble bee and its role in pollination. Others are positively harmful and, in the course of their lives, can devastate the plants they interact with and therefore the wider environment that these plants help to support.
It’s unbelievable but true that around a third of all crops worldwide are lost to pests and diseases even before they are harvested, after which point other organisms may take their share of the remaining crop. Imagine a world in which there were no crop pests and diseases but instead we had billions of extra platefuls of food each day. In Scotland, as in the rest of Europe, we still lose 15-20% of our crops in this way even though we have some of the most advanced agricultural systems anywhere in the world.
Slowing the spread of ash dieback
Of course it isn’t all about food, and the big stories on plant health in recent years have been in forestry, and include ash dieback and Ramorum on larch. Ash dieback is caused by a fungus called Hymenscyphus fraxineus (previously called Chalara fraxinea) which weakens the tree and causes it to become more susceptible to attack by other organisms. As well as timber, ash also provides a habitat for a wide range of dependant species, which are also affected if the tree dies.
It isn’t yet clear how big an impact ash dieback will have in Scotland as we wait to see the true extent of its spread but, in the meantime the Forestry Commission and partners are working hard to find possible ways to stop or slow the attack, including the use of trees that are tolerant or resistant to infection. Ramorum on larch is caused by Phytophthora ramorum and has affected large numbers of larch trees used for timber. The pathogen also causes disease in a wide range of other plants world-wide, and in the USA small genetic variations in the pathogen have caused it to infect oak trees, hence the name ‘sudden oak death’.
Rapid action to cut down infected larch trees in Scotland has been a successful strategy to date but the problem still persists. P. ramorum also infects some Rhododendron species, which are common in many British woodlands, parks and gardens, and it is thought that such plants may have played a part in the spread of the pathogen to larch.
Threats of invasion
The above diseases are already in Scotland but what about those that threaten invasion. The UK Plant Health Risk Register has over 1000 such pests and pathogens on its list showing just how big the threat is to Scotland. Perhaps our biggest threat currently is Xylella fastidiosa. This bacterial pathogen has, in just a few short years, caused devastation in southern Europe across a range of plant species, most notably on olive trees in Italy. Many millions of these trees have been wiped out by the disease, some of which are over 2000 years old, and have had a significant impact on the rural economy.
The most alarming thing about Xylella is that it can infect over 350 different plant species across all plant sectors and, because of this, its entry into Scotland and its subsequent spread and impacts are difficult to discern and even harder to control. If it does reach Scotland, who knows where it will strike, which of the many species it will attack and, ultimately, what damage it will do to the plants that are so essential to our lives.
The Plant Health Centre brings together plant sectors for forestry, horticulture, environment and agriculture to co-ordinate plant health knowledge, skills, needs and activities across Scotland, and works with Scottish Government, public bodies, industry, the public and others to provide scientific evidence that will help make informed decisions about how to keep Scotland’s plants safe. The Centre will help to identify the major threats, ensure that emergency plans are right for Scotland, provide short and longer term advice and help to fill knowledge gaps, and ensure that the different sectors work together to maximise and share the knowledge that we have – not least in cases such as Xylella where a common approach to a multi-sector threat is so important.
Enlisting citizen science
This isn’t just about the Centre, the Government or industry but very much about the public and what you can do to help. Citizen science is growing in Scotland as a way to put eyes and ears on the ground when it comes to spotting pests and diseases (see Tree Alert). It’s also really important that you know the provenance of the plants you buy, especially with the increasing sale of plants via the internet. If in doubt either ask or go elsewhere. Perhaps most importantly, an attractive plant seen while on holiday, even elsewhere in the UK, should be appreciated in situ, where it belongs, and not brought back to Scotland even as seeds (many organisms are transported via the seeds). In this way we can all work together to keep Scotland safe.
When you next go out, have a look around at the plants that make up our landscape and be glad that, in the most part, these plants are healthy and performing the functions they are there to do. Let’s, together, try to keep it that way.
The plant centre partnership: 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). It has a Science Advisory and Response Team (SART) from the above organisations as well as partners from the universities of Edinburgh, Strathclyde and Exeter, Centre for Ecology & Hydrology, SASA and Biomathematics and Statistics Scotland (BioSS), each bringing with them a range of skills relevant to plant health from understanding public perceptions to long-term disease forecasting.
Featured image: Growing in harmony: a healthy mix of wild flowers and agricultural crops sheltered by a woodland strip. Photo Fay Young