Potential role of botanic garden collections in predicting hosts at risk globally from invasive pests: a case study using Scirtothrips dorsalis

Abstract

Increasing trade in plants and plant products across continents heightens the risk of exotic insect pests expanding geographically into new habitats. This threatens not only the production and economic value of widely traded crops but the survival of species grown or sought by low-income communities. The first European outbreak of Scirtothrips dorsalis was detected in the Palm House collections at Kew in 2007 and triggered a monitoring program. This monitoring along with a robust review of the literature brought together information on new and known hosts for S. dorsalis. Further to this, we used molecular characterization techniques to identify which proposed cryptic species of S. dorsalis was present in this outbreak. The study revealed that 39% of the species of plants among the collections supported the proposed S. dorsalis South Asia 1 cryptic species, with over 50% of those species supporting immature life stages of the thrips confirming that they are suitable breeding hosts. Of particular importance are the newly identified hosts that are crops, and two further hosts reported as endangered/critically endangered. This study demonstrates the role that botanic garden collections can play in generating host relationship data that can feed into the development of robust predictive risk assessments for invasive insects. This can provide plant health authorities with the scientific basis for prioritizing management plans to protect important, vulnerable crop and non-crop plant species.