Research

RHS Science Exchange

What cost the world in your garden?
How great is the threat to our native and garden flora from the
accelerating international plant trade?

Summary

Introduction

The risks associated with the global movement of plant material and products were outlined and a discussion held on whether we have the correct balance between biosecurity and free trade. An overview was provided of current plant health systems. A pragmatic response was called for, which would strike a balance between minimising the risks, ensuring a thriving horticultural trade and protecting the natural ecosystem.

Role of the public

Public engagement was considered universally important in two areas: education about the issues and reporting sightings of pests and diseases.

Differing views were held on whether the public cares about the source of their plants; it was suggested that if they were made aware of the issues in an accessible and stimulating way, they might be engaged with the environmental issues. It was suggested that gardening federations and societies could be influential groups to provide a channel of communication to other gardeners. It was also suggested that horticultural and forestry students should be taught more about the risks and threats.

Defra representatives highlighted the important role the public can play in reporting sightings of pests and diseased plants, which alerts plant health inspectors to outbreaks which can then be controlled.

Invasive Plants

It was suggested that we shouldn’t just consider the risks associated with invasive pest and diseases, but also consider the impacts of invasive plants such as Japanese knotweed and Himalayan balsam. It was noted though that invasions are very slow - it may be decades before diseases take hold, but may take 200 years for invasive weeds to threaten ecosystems.

Valuing of ecosystems under threat

The impact of invasive pests and diseases on natural ecosystems have not been valued to the extent that they affect food or agricultural production, because of the difficulty in costing the impact financially. It was suggested that whereas significant resources are committed to the prevention of agricultural disasters like food & mouth, in the future society might value the natural environment as much, and commit more effort in protecting it.

Increasing numbers of home-grown plants

Horticultural trade views were expressed that broadly supported the suggested solution of switching to local production of plants, and less importation of mature plants. Associated with this cross-border trade is a trend toward less chain-of-custody responsibility related to production, plant health and the related capital investment; longer-term relationships between suppliers and retailers are less common than before, and it was suggested that this increases risks. Systems should be developed that support good practice by nurserymen in this respect.

Industry insurance schemes

It was suggested that there was an active disincentive for nurseries not to report stock suspected to be infested, as it may be destroyed and compensation is unlikely. UK producers are seen to be grouped with the perceived ‘polluter’ by Government, and it was suggested that this is counterproductive. It was suggested that an insurance scheme would be difficult to instigate as the horticultural industry is fragmented, and additional costs would be burdensome on an industry that relies upon very narrow margins of profitability.

Strengthening plant resistance

Little research has been undertaken in strengthening plant resistance to pest and diseases, although the impact of climate change has been reviewed in this respect. Can we build resilience into systems through proper land management and other activities, rather than focusing entirely upon keeping pests and diseases out?

Who pays?

The question was raised about who pays for costs relating to imported pests and diseases: the Government (i.e. taxpayer), trade or consumer? It was noted that there is a wide adoption of the ‘polluter pays’ principle internationally and in the UK. The international movement of plants is risky and it was suggested that the trade should have responsibility for contributing to risk assessments associated with that risky trade. Others highlighted that the ‘polluter’ is not necessarily the trade alone, responsibility could also be attached to the Government with respect to the effectiveness of regulatory regimes. Ultimately, the consumer is expected to pay a premium for the availability of goods that incur risks.

Summing up

It was proposed that Prof Brasier’s concerns about the risks of importing pests and diseases were well-founded, but that there were no straightforward solutions. Questions about the scientific basis of plant health inspections, the economics of controlling pests and diseases, public education and the attribution of costs would all need to be addressed.

A working group will be convened by the RHS, which shares an interest in a thriving horticultural trade in a secure environment and which aims for a secure future for horticulture generally.

It was suggested that representatives from Defra, the Horticultural Trades Association, the Institute of Horticulture, Professor Clive Brasier and Professor Jeff Waage might be invited to join the review group.

It was suggested that the group should aim to make interim proposals within one year to move the issue forward.