Situation of Dryocosmus kuriphilus in France in 2008
In France, the first outbreak of Dryocosmus kuriphilus (Hymenoptera: Cynipidae - EPPO A2 List) was reported in 2007 in the department of Alpes-Maritimes (Provence-Alpes-Côte d’Azur region), close to the infested region of Cuneo in Italy (EPPO RS 2007/086 and 2008/097). During surveys conducted in 2008 in Alpes-Maritimes, the pest was found in the 4 communes that were already infested in 2007, and in 2 new ones. Despite phytosanitary measures which were implemented to prevent the spread of the pest in France and Italy, the surface of demarcated areas (infested zone + focus zone of 5 km radius + buffer zone of 10 km radius) in both countries increased from 124;632 ha in 2007 (63;362 in FR; 61;270 in IT) to 179;086 ha in 2008 (114;670 in FR, 64;415 in IT). In 2009, it is envisaged to use biological control methods by releasing a parasitoid of D. kuriphilus, Torymus sinensis, as this has done since 2005 in Italy by the University of Torino. In addition, studies on the possible use of resistant cultivars (Castanea sativa cv. ‘Bouche de Bétizac’) are being initiated.
In 2007, an isolated outbreak of D. kuriphilus was detected on 10 young chestnut (Castanea sativa) trees in a nursery in Haute-Garonne (Midi-Pyrénées region). The infested lot had been originally produced by an Italian nursery near Brescia (Lombardia) before being re-exported from Spain to France. In 2007, all infested plants were destroyed, no chestnut plants were commercialized by the infected nursery, and no further insects were detected in its vicinity. However in 2008-05-09, D. kuriphilus was identified on 5 of the 36 chestnut trees which had remained at the nursery. Observations made on the galls showed that the insects were still inside and did not have the time to complete their life cycle and escape in the environment. All chestnut trees grown at the nursery were destroyed. As no other insects could be found in the surroundings, the NPPO of France considers that this outbreak has now been eradicated.
The pest status of Dryocosmus kuriphilus in France is officially declared as: Present, only in one area, under official control.
NPPO of France, 2009-01.