Garden sentinels: New Zealand’s contribution to future proofing UK plant species from insect pests and diseases

The use of sentinel (expatriate) plants, is an initiative for plant biosecurity risk assessment and surveillance, that is being adopted internationally. The concept is based on the presence of plant species in foreign locations (e.g. botanic gardens, arboreta) where they may be exposed to insect pests and pathogens they have not as yet encountered, and act as an early warning system for their native range.

The Christchurch Botanic Gardens has been a participant in a three year pilot study to test the suitability of the sentinel plants concept to detect new host-plant associations on selected plant species considered important to the UK. This involves the International Plant Sentinel Network (IPSN), Botanic Gardens Conservation International (BGCI) and Department of Environment, Food and Rural Affairs (DEFRA, UK), with remote diagnostics provided by FERA Science Ltd. The surveys at the Christchurch Botanic Gardens was supported by Better Border Biosecurity (B3) parties with appropriate links to New Zealand’s National Plant Protection Organisation (NPPO), the Ministry for Primary Industries (MPI), to ensure that legal responsibilities concerning new organisms were followed.

The plants selected for surveillance were Rosa spp. (rose), Fagus sylvatica (European beech), Quercus robur (English oak) and Pinus sylvestris (Scots pine). In early (December) and late (January) summer, 2-3 plants of each taxa were inspected and assessed for insect presence, damage and plant pathogens, using protocols developed by IPSN. The survey evaluated the plants health from observations of the leaves, buds/cones and stem/trunk, along with the general environment the plants were growing in. Results were recorded either on a paper or electronic plant health checker (PHC) form, and images taken of the plant and any pests or diseases. The reports and images were then scanned and sent electronically to the UK for remote diagnostics. This presentation will discuss the outcomes of the pilot study in Christchurch, the benefits and challenges of undertaking remote surveys involving staff from Botanic Gardens and Arboreta, and the contribution of using sentinel plants to improving biosecurity outcomes.