Involvement of «Phaeoacremonium» spp. and «Cylindrocarpon destructans» with Grapevine Decline in Portugal

In an attempt to determine the aetiology of young vine decline in Portugal a study was carried out in rootstock nurseries and in young vineyards during the last few years. Rootstock nurseries located in the most important production areas of Portugal (Ribatejo-Oeste and Beira Litoral) were surveyed. The fungi most frequently isolated from discoloured wood at the base of the stem were Cylindrocarpon destructans and Phaeoacremonium spp., although Acremonium sp., Phomopsis sp., Fusarium spp., Fusicoccum sp., Gliocladium sp., Phoma sp. and Sphaeropsis sp. were also present. Young vines (2- to 8-year-old) showing decline symptoms were collected from various vinegrowing regions of Portugal. Disease incidence was variable but decline symptoms were present in several wine and table grapevine cultivars grafted onto different rootstocks (99R, 110R, 1103P, 101-14, 140Ru, 5BB and 161-49). Isolations from symptomatic internal tissues revealed that also C. destructans and P. chlamydosporum were the predominant fungi isolated from the basal end of the rootstocks and grafting tissues. In the pathogenicity tests carried out with C. destructans isolates the pathogen was reisolated from inoculated plants showing black-foot symptoms but never from the controls. Our results point out that both C. destructans and P. chlamydosporum might be involved with young grapevine decline in Portugal