Syrah decline

Syrah decline, mysterious fatal phenomenon affecting syrah exclusively, known as dépérissement in French, whereby a part of the trunk swells and becomes bulbous, generally around the graft, forming splits in the wood. The vine may continue to function normally for a few years but eventually the leaves redden prematurely during summer, vigour rapidly declines and, within a year or two, the vine is dead. It was first noticed in the Languedoc in the 1990s and has affected Syrah virtually wherever it is grown apart from Australia. This led researchers to investigate clonal material selected after the original Syrah cuttings arrived in Australia. As a result the seven most susceptible French clones (73, 99, 301, 381, 382, 383, and 585) were withdrawn from sale, while the three least susceptible (470, 524, and 747) were strongly recommended for new plantings. New high-quality, low-susceptibility clones have since been promulgated.