Beyond cryptogamic diseases and wood diseases, vines must face a particularly insidious and devastating threat: flavescence dorée. This disease, classified as a "quarantine" organism, represents one of the greatest phytosanitary scourges for European vineyards. Its silent yet relentless progression makes it a major concern for winegrowers.

Understanding flavescence dorée: symptoms and transmission

Flavescence dorée is caused by a phytoplasma, a micro-organism lacking cell walls that lodges and multiplies in the vine's sap-conducting vessels. Symptoms generally appear in summer: a yellowing or reddening of the foliage depending on the grape variety, an inward curling of the leaves, a drooping of the shoots, and a lack of lignification (the wood fails to harden). The bunches dry out, shrivel, and fall off before reaching maturity. Once a vine is infected, its production drops to almost nothing, and it is irreversibly doomed to wither and die.

The primary vector of this disease is a piercing-sucking insect, the vine leafhopper (Scaphoideus titanus). By feeding on the sap of an infected vine, the leafhopper ingests the phytoplasma, which incubates within it before being transmitted to other healthy vines during its subsequent feeds. The fight against flavescence dorée therefore relies above all on controlling this insect and the systematic uprooting of contaminated vines to prevent the outbreak from spreading.

Château Cazebonne and flavescence dorée: resilience through biodiversity

Faced with this ever-present threat, Château Cazebonne remains true to its philosophy of sustainable and organic viticulture. While the fight against the leafhopper is a regulatory requirement for all vineyards, we simultaneously work to strengthen the natural resilience of our vines. A diverse vineyard, with living soils and a wealth of genetic diversity, is intrinsically better equipped to cope with attacks. As so aptly highlighted in Jean-Baptiste Duquesne's book, "Bordeaux, une histoire de cépages", monoculture has likely impoverished our vineyard's ability to adapt, making certain grape varieties more vulnerable. The phylloxera crisis, for example, had a major impact on varietal biodiversity (Source 2).

This is why we have undertaken pioneering work in Bordeaux: researching, identifying, and replanting those old and forgotten grape varieties that once made up the Bordeaux viticultural mosaic. This neglected plant heritage offers precious genetic diversity and represents a major asset in the quest for more resistant vines, naturally better armed against diseases like flavescence dorée. This long-term endeavour, requiring perseverance and passion, is made possible thanks to the support of the many wine lovers who have embraced our wines. By tasting our wines made from these rare grape varieties, you actively participate in the revival of these viticultural treasures and the preservation of an entire chapter of Bordeaux history.

Discover our wines and live the Château Cazebonne experience by visiting the Cazebonne boutique.

To deepen your knowledge of the fascinating history of Bordeaux grape varieties, we invite you to receive the digital version of the book "Bordeaux, une histoire de cépages" by Jean-Baptiste Duquesne, published by Éditions BBD.

Flavescence, a threat to the vine (Scaphoideus titanus and phytoplasmas)

Flavescence dorée is a serious vine disease, whose scientific name refers to the phytoplasma responsible for the infection. This micro-organism is transmitted from one vine to another primarily by the vine leafhopper, Scaphoideus titanus, a small hemipterous insect about 5 mm long. This disease, of North American origin like phylloxera, was first identified in Europe in the 1940s. It is characterised by a yellowing or reddening of the leaves, necrosis of the veins, a drooping habit of the shoots, and a lack of lignification. Infected vines see their production drop drastically and eventually die.

The life cycle of the Scaphoideus titanus leafhopper is annual. Egg-laying takes place in autumn under the bark of the vines. The eggs hatch in spring, and the young larvae develop through several nymphal stages on the vine. It is from the third larval stage that the insect becomes capable of acquiring the phytoplasma by feeding on the sap of an infected vine. After an incubation period within the insect, it can transmit the disease to healthy plants during subsequent feeds. The adult flight period extends from July to September. Preventing this disease involves insecticide treatments at the right time in the insect's cycle and the mandatory uprooting of diseased vines to limit its spread, much like other threats such as the parasite responsible for erinose.

At Château Cazebonne, we vigilantly monitor for symptoms of flavescence dorée. Our biodynamic approach and our commitment to respecting the terroir drive us to foster a healthy ecosystem, better able to withstand pressures. The presence of a rich auxiliary fauna is an asset, but vigilance remains paramount in the face of this quarantine disease. Regulations impose specific control methods, which we rigorously apply, whilst continuing to promote biodiversity within our pesticide-free vineyard. This foundational work, particularly the reintroduction of extinct Bordeaux grape varieties, contributes to the resilience of our vines.

This long-term endeavour to preserve and renew our viticultural heritage, drawing on research such as that presented in "Bordeaux, une histoire de cépages" by Jean-Baptiste Duquesne, is essential. We invite you to find out more about this fascinating book by downloading it, to test your knowledge with our oenological quizzes, and of course, to support our approach by exploring our wines available for sale online.