The unique role of sentinel trees, botanic gardens and arboreta in safeguarding global plant health

The ever increasing threat from new and emerging plant pests and pathogens poses a significant threat to plant health on a global scale. Once an organism is introduced and establishes itself in a new region, it is incredibly costly, both in terms of environmental impact and economic loss, to manage it. In most cases, eradication and containment programmes are most effective when the organism is identified early on. Further to this, the most cost effective management of all is preventing introduction in the first place. Therefore, the role for early warning systems in plant health is becoming more evident. Botanic gardens and arboreta are unique resources that can help provide such early warning and are, currently, often overlooked within plant health. The staff and volunteers that work within these botanical institutes are knowledgeable and passionate people, who if made aware of current threats, can become additional 'eyes and ears' for first detection of new introductions. Gardens can also help to increase available information on organisms and, potentially, identify the 'unknown' organisms through sentinel research. Plant collections provide a large range of exotic hosts (so-called 'sentinels') growing in diverse regions around the world which can be studied to determine susceptibility to potential pests that have not been introduced to their native ranges. The International Plant Sentinel Network (IPSN) has been developed in order to support such work and bring together botanical institutes with organisations working within plant health.