Update on the situation of Geosmithia morbida and Pityophthorus juglandis 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 in the Lyon metropolitan area (Rhône department, Auvergne-Rhône-Alpes region) (EPPO RS 2022/232), and the presence of G. morbida was first confirmed in November 2022 on 3 walnut (Juglans regia) trees in the same area. Official surveys were carried out in 2023 to delimit the presence of the pests.
Several specimens of P. juglandis were caught in a trap in the Isère department, and in a trap in the Ain department (both in Auvergne-Rhône-Alpes region), respectively 12 and 4 adults in June and July 2023. In Ain, one J. regia tree was found to be infected by G. morbida. In Isère, tree samples were taken but none were positive for G. morbida. Surveys conducted in the Rhône department detected G. morbida in one J. nigra tree in September 2023. The infested trees were cut down and destroyed, and a demarcated area of 2 km defined around them, according to the national decree.
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.
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 (2023-12).
Arrêté du 28 juin 2023 relatif à la lutte contre Pityophthorus juglandis (PITOJU) et Geosmithia morbida (GEOHMO), agents pathogènes responsables de la maladie des mille chancres. Journal officiel de la République française n°0161, texte 15. https://www.legifrance.gouv.fr/eli/arrete/2023/6/28/AGRG2235717A/jo/texte