Update on the situation of Pityophthorus juglandis and Geosmithia morbida in France
The bark beetle Pityophthorus juglandis (Coleoptera: Curculionidae: Scolytinae, EPPO A2 List) and the fungus Geosmithia morbida (EPPO A2 List) are associated with the thousand cankers disease of walnuts.
In France, P. juglandis was first detected in September 2022 and G. morbida in November 2022 in the Lyon metropolitan area (Rhône department, Auvergne-Rhône-Alpes region) (EPPO RS 2022/232, EPPO RS 2024/017). In 2023 specimens of P. juglandis were caught in traps in the Isère department in June and in the Ain department in July, where a Juglans regia tree was also found to be infected with G. morbida (EPPO RS 2024/017). Official measures were applied, including felling of infested trees and official surveys.
The NPPO of France provided an update on the situation following official surveys in 2024.
- Rhône department and Lyon metropolitan area
In Lyon metropolitan area, throughout 2024, official surveys to monitor the presence of both P. juglandis and G. morbida found several specimens of P. juglandis in traps and two J. regia trees tested positive by molecular testing for G. morbida. Eight trees have been felled including the two trees that tested positive for G. morbida and six trees that have been felled preventatively. Infested zones (10 m radius around an infested tree) have been established in Bron, Caluire-et-Cuire, Chassieu, Feyzin, Lyon, Saint-Priest, Vénissieux, Villeurbanne. Buffer zones (2 km radius around the infested zone) also cover part of the municipalities of Champagne-au-Mont-d'Or, Collonges-au-Mont-d'Or, Décines-Charpieu, Écully, Francheville, Genas, Irigny, La Mulatière, Rillieux-la-Pape, Saint-Cyr-au-Mont-d'Or, Saint-Didier-au-Mont-d'Or, Saint-Symphorien-d’Ozon, Sainte-Foy-lès-Lyon, Solaize, Tassin-la-Demi-Lune, Vaulx-en-Velin, Vernaison. Intensive surveys are ongoing.
In addition to the delimited areas in the Lyon metropolitan area, an infested area has been established in the northern part of the Rhône department in Lacenas with a buffer zone covering parts of the municipalities of Cogny, Denicé, Gleizé, Porte des Pierres Dorées.
- Isère department
During official surveys in 2024, 44 P. juglandis specimens were caught in three new municipalities, in 10 out of 12 traps that had been set up to monitor the population of P. juglandis. Official surveys did not detect the presence of G. morbida in the department. No demarcated area has been established as P. juglandis was only found in traps. Intensive surveys continue.
- Ain department
During official surveys in 2024, several adult specimens of P. juglandis were found in another municipality, Bourg-en-Bresse, where an infested zone has been established. One out of the four traps set up in the Ain department caught 7 adult P. juglandis. Buffer zones are now established across the municipalities of Péronnas, Saint-Denis-lès-Bourg and Viriat.
The pest status of Geosmithia morbida in France is officially declared as: Present, only in some parts of the Member State concerned, at low prevalence, under eradication.
The pest status of Pityophthorus juglandis in France is officially declared as: Present, only in some parts of the Member state concerned, at low prevalence.
Sources
NPPO of France (2025-04)
An updated map of the demarcated areas can be found here: https://draaf.auvergne-rhone-alpes.agriculture.gouv.fr/arrete-prefectoral-modificatif-du-25-09-2024-a5793.html