Situation of grapevine flavescence dorée in France
In France, it is considered that the situation of grapevine flavescence dorée (EPPO A2 list) remained stable in 2003. However, despite compulsory control measures, a small number of new outbreaks were discovered at Moissac (Tarn-et-Garonne), in Vaucluse, Gironde and Charentes. Surveys on the insect vector Scaphoideus titanus showed that it is still absent from the vineyards of Alsace, Champagne, Vendée and from cv. Muscadet in the Loire Valley (Herlemont, 2003). It is also stressed that a new decree was published in 2003 to clarify and strengthen compulsory control measures against grapevine flavescence dorée and its vector. This new piece of regulation applies to all Vitis plants (cultivated or wild). When an infected Vitis plant is found, a quarantine area (called ‘périmètre de lutte’) is delimited around it for a minimum period of 2 years. The delimited zone includes at least one commune. All infected plants must be destroyed and compulsory control against the vector is required in the delimited zone. The decree also contains a set of special requirements for nurseries. In particular, it is prohibited to grow mother plants in the vicinity of a delimited zone. A hot water treatment is also included for planting material.
Possibilities for biological control of S. titanus are being investigated. This insect is thought to originate from the Great Lakes region in USA and Canada, where it is relatively not abundant. Earlier observations made in New York State had revealed the existence of parasitoids (Hymenoptera: Dryinidae). Further surveys were carried out in 2001/2002 by French scientists (Malausa et al., 2003) to look for possible biological control agents of S. titanus in its area of origin. In the regions of Finger Lakes (New York State), insects were collected in vineyards and wild Vitis plants, or ‘trapped’ on reared eggs of S. titanus exposed in the field. Several parasitoid species were found, such as Lonchodryinus flavus and Gonatopus peculiaris (both Hymenoptera, Dryinidae) and several species of oophagous parasitoids (Diptera, Pipunculidae). Further studies are needed to rear these species in the laboratory and to evaluate their biological characteristics, as well as their efficacy and safety, prior to any release in vineyards.
Sources
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Décret du 9 juillet 2003 relatif à la lutte contre la flavescence dorée de la vigne et contre son agent vecteur. Journal Officiel n° 167 du 22 juillet 2003, p 12362.
Herlemont, B. (2003) Bilan phytosanitaire de la vigne en 2003. Climatologie exceptionnelle et réglementation en mouvement. Phytoma – La Défense des Végétaux, no. 565, 14-19.
Malausa, J.C. ; Nusillard, B. ; Giuge, L. (2003) Lutte biologique contre la cicadelle vectrice de la flavescence dorée. Phytoma – La Défense des Végétaux, no. 565, 24-27.
de la Roque, B. (2003) Flavescence dorée : réglementation dépoussiérée. Phytoma – La Défense des Végétaux, no. 565, 22-23.
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