Final Report and Policy Document

Improving knowledge of Xylella fastidiosa vector ecology: modelling vector occurrence and abundance in the wider landscape in Scotland

Xylella vector, spittlebug

The insect-vectored, bacterial plant pathogen Xylella fastidiosa is currently absent from Scotland and the wider UK, but if introduced could be a serious threat to trees and other plants. However, there is a lack of knowledge about the ecology and distributions of Xylella vectors in Scotland and the potential effects of this on any outbreak of the disease, which this project aimed to address.

Sampling of xylem-feeding potential vector insects (order Hemiptera, Aphrophoridae and Cicadellidae families) was conducted in 2021, including weekly sampling of different habitats at Loch Leven, Fife, and a wider survey across 16 sites in central Scotland.

Overall, this project has produced better understanding of vector phenology, species composition and habitat preferences in Scotland, as well as guidance for sampling vectors and controlling future outbreaks. It highlights a previously unappreciated risk to Scottish heathland, though this should be set in the overall context of a less suitable climate for Xylella outbreak growth and impact at present. Better understanding of vector dispersal ranges and of Xylella transmission and disease progression in heathland plants under Scottish climatic conditions would further inform on the potential risk of introducing Xylella to Scotland.