Phomopsis viticola (Sacc.) Sacc. 1915

Excoriosis

Phomopsis viticola is the parasitic fungus responsible for excoriosis ( Phomopsis cane and leaf spot ). Before 1925, this wood disease, of European origin, was known under the name of punctate anthracnose, because of the strong similarities observed between its symptoms and those caused by anthracnose also called black spot by the Anglo-Saxons  ( Elsinoë ampelina ).

The origin of the excoriose is very probably European; it was first observed there at the end of the 19th century and identified at the beginning of the 20th century. This disease is now present in the majority of wine-growing areas in the world, reported in many wine-growing countries on all continents. It is especially problematic during the bud break and growth phase of young shoots in production areas where the climate is humid. It is the attacks on twigs and on fruits which have the most important economic repercussions, the leaf lesions are generally not serious. It should be noted that the lesions on twigs considerably increase their sensitivity to frost and help reduce yields.

Many European vineyards are affected by the excoriose: Italy, Spain, Portugal, Switzerland, Germany, Hungary . In France, excoriose affects all vineyards with varying degrees of incidence. Regions, such as the Atlantic coast, where the climate is rainy after bud break are particularly exposed to the risk of infection.

The ban on the use of sodium arsenite in winter treatment seems to be the cause of the resurgence of excoriose in certain wine-growing areas around the world.

Classification : Fungi, Ascomycota, , Pezizomycotina, Sordariomycetes, Sordariomycetidae, Diaporthales, Diaporthaceae
Téléomorphe : Diaporthe
Synonyms: Cryptosporella viticola Shear (1911), Sphaeropsis viticola Cooke (1883)

Additional information associated with excoriose or its pathogen :

• P. viticola wrongly has been associated by the Anglo-Saxons with dead arm disease , before this disease is attributed to Eutypa lata . Let us add that this situation is not surprising because P. viticola , pathogenic in particular on grapevine shoots, is also frequently isolated in the wood of grapevines affected by eutypiosis or esca in particular.
• Several Phomopsis spp. or assimilated fungi have been observed and / or isolated from grapevines, excoriated or not. For example at least two main taxa have been described in Australia:
  - Phomopsis taxon 1, detected in certain production areas, whose sexual form (teleomorph) was named Diaporte australafricana (eg Diaporte perjuncta , eg Diaporte viticola ), it would have no effect on the grapevine, considered as a simple endophitis;
  - Phomopsis taxon 2 is in fact P. viticola , the cause of excoriose in many production areas around the world; the latter would not have a known sexual form, which is contrary to the older bibliography.
• Phomopsis amygdali has also been isolated from grapevine on several occasions, without being involved in excoriosis. A Phomopsis, with a genetic sequence close to Diaporte phaseolorum , has also been reported in the United States on grapevine.
• Another fungus, formerly named Macrophoma flaccida, now considered synonymous with Fusicoccum  aesculi (anamorph of Botryosphaeria dothidea ), is responsible in some countries for symptoms of excoriosis. After clarification of the concept of B. dothidea , it is Neofusicoccum parvum which would be responsible.