Fig. 3

Survey in the Saint-Cadou state forest area. A Pre-eradication survey. Plots with crown assessment (circle, size of the circle proportional to the proportion of tree with a crown assessment > 1), plots with no crown rating (triangle). P. ramorum detected (red) or not detected (blue). B Post-eradication survey. No suitable host present (plus), chestnuts present (circles), other hosts such as larch saplings, Rhododendron sp., Vaccinium myrtillus or Calluna vulgaris (squares). Larch stands clear-cut in 2018 or 2021 are indicated by red and blue lines. The stands outlined in red are the stands that were assumed to represent the inoculum sources in 2017s–2018 to assess the distance of P. ramorum dispersal. 1, Detection of P. ramorum in autumn 2017 in stands with crown in good condition; 2, Privately owned larch stand clear-cut in April–May 2021 where P. ramorum was first detected in 2019 and; 3, Plot where rain traps were placed under chestnuts in October 2018 and where trees were felled for examination of P. ramorum presence in the crown (declining mature chestnuts, and detection of P. cinnamomi on a dying seedlings); 4, wild rhododendrons patch near planted rhododendrons; 5, Multiple healthy looking larch and chestnut saplings within the larch stands that were clear-cut during the eradication treatment