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Overview of key points

This POSTbrief focuses on the risks arising from the introduction of invertebrate animals and pathogens injurious to plants and uses the term ‘pests’ to collectively describe these. The spread of pests of cultivated and wild plants globally, including forest pests, pose potentially high impacts for natural capital, food security, livelihoods, and trade.

Plant biosecurity refers to measures that aim to prevent the introduction and spread of pests that pose potential risks to plant health. The Government’s 2023 UK Biological Security Strategy, sets out an ambition of the UK being resilient to a spectrum of biological threats by 2030, including “high consequence risks” to plant health.  

Plant biosecurity activities occur along a continuum that starts offshore or pre-border to reduce risks that are occurring in other countries, then at a nation’s borders to stop plant pests from entering, to managing established pest organisms within a nation’s borders.

Plant health is devolved, with each nation having a national Plant Health Service (see section 1.3). However, there is an agreed Plant biosecurity strategy for Great Britain 2023 to 2028, which links to the UK Biological Security Strategy. The Plant biosecurity strategy has set four key outcomes:  

  • a world class biosecurity regime 
  • a society that values healthy plants  
  • a biosecure plant supply chain  
  • an enhanced technical capability 

Pest risk analyses (PRA)  provide the technical and scientific evidence to justify preventative measures under the relevant international frameworks before biosecurity measures can be enacted. The UK plant health risk register (UKPRR) records and rates the risks to UK crops, trees, gardens and ecosystems from pest plants. Organisms are placed on the register as potential threats. If they do not have a PRA, they are prioritised for the development of one (section 2.1). 

Live plants and plant material (including wood and wood products) are currently classed as either unregulated, regulated or prohibited. Unregulated plant material include processed and packaged fruit and vegetables. Under the UK Government 2023 Border Target Operating Model these categories will change to high, medium or low risk, with controls weighted against the risks posed both by the commodity and the country of origin (section 2.2). All imported live ‘plants for planting’ are regulated, other regulated materials include various seed, fruit, cut flowers, tubers, and growing media, which requires phytosanitary certification. 

Advanced notification of landing is also required for notifiable’ regulated material. Some pest organisms pose sufficient threat that entry of host plants and plant material to the UK is prohibited, with some prohibited pending risk assessment, such as various tree species from non-EU countries (section 2.2). 

Because of the traded goods across a range of international pathways, as well as spread via natural means, new pests will continue to be introduced to the UK. Post border surveillance to detect the introduction of a known pest risk may facilitate successful eradication if prompt immediate action is taken. Surveillance may also inform measures to control its spread as part of outbreak responses, or provide information on impacts and cost effectiveness of long-term control measures (sections 2.2 and 2.3). 

The Plant biosecurity strategy for Great Britain 2023 to 2028 sets out a vision of ‘shared responsibility for biosecuritybetween government, industry, and communities. This includes the use of citizen science (public participation in scientific research) to support post border surveillance and engage stakeholders (sections 3.1 and 3.2) and use of accreditation schemes to encourage best practice and collaboration (section 3.3).  

The financial implications to a business importing ‘plants for planting’ if a quarantine pest or disease is reported is the destruction of the consignment at cost to the business. The strategy also commits to increasing domestic production to decrease dependency on imported plants and plant materialbut there may be substantial challenges for increasing the competitiveness of UK domestic production (section 3.3). 

However, pest risks will continue to grow with environmental change and the strategy also sets out the need for adaptation and resilience to these biosecurity challenges (section 4.1). There are significant knowledge gaps in relation to how pest-plant interactions will change in wild plant populations. There are also significant challenges for food security from growing pest risks, both globally and for growers in the UK.  

Post-border biosecurity extends down to the measures and decisions taken by growers to support the healthy growth of a crop. Researchers have and are developing new agricultural surveillance technologies and data approaches, such as diagnostic tests and sensors for in-field decision making, but constraints remain such as funding, cost, scaling up production and the willingness or ability of growers to adopt them.  

Biosecurity is an integrated concept directly encompassing agriculture, food safety, protection of human populations, the environment and biodiversity. However, bringing together the human, animal, plant and environmental health sectors to address biosecurity risks in a common and systematic manner, as set out in the 2023 UK Biological Security Strategy, remains a governance challenge both globally and domestically (section 4.2).


POSTbriefs are based on literature reviews and interviews with a range of stakeholders and are externally peer reviewed. POST would like to thank interviewees and peer reviewers for kindly giving up their time during the preparation of this briefing, including: 

Professor Chris Gilligan, University of Cambridge 

Professor Neil Boonham, Newcastle University 

Professor Richard Buggs, Kew Gardens* 

Professor Sarah Gurr, University of Exeter

Dr Rosalind Noble, British Society for Plant Pathology* 

Alisha Anstee, the Woodland Trust* 

Dr David Slawson, Imperial College* 

Professor Saskia Hogenhout, John Innes Institute 

Professor Ian Toth, James Hutton Institute 

Dr Chris Hartfield, NFU* 

Lucia Zitti, NFU 

Christine McDowell, NFU  

Sally Cullimore, HTA 

Pippa Greenwood, HTA 

David Lydiat, HTA 

Professor Gerry Saddler, Chief Plant Health Officer for Scotland 

Professor Nicola Spence, Defra Chief Plant Health Officer, Head of the National Plant Protection Organisation for the UK and University of Birmingham* 

Dr Ana Perez-Sierra, Forest Research 

Ben Goodall, Animal and Plant Health Agency* 

Stephanie Godliman, Defra 

Lisa Smith, Defra 

* denotes people and organisations who acted as external reviewers of the briefing

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