Pathogenicity of fungi associated with a decay of kiwifruit

A decay of kiwifruit was noted for the first time in 9 to 10-year-old Italian vineyards. Trunk and cordons of symptomatic vines showed decayed areas surrounded and preceded by wood discolouration. Fomitiporia mediterranea (syn. F. punctata) was recovered from decayed tissue, whereas Phaeoacremonium parasiticum, Cadophora malorum and strains of Phaeoacremonium aleophilum were found in the discoloured wood. Two-year-old potted kiwifruit vines of the cultivar Hayward were inoculated with a strain of each species in order to assess their ability to cause wood discolouration and decay. Six months after inoculation, discolouration was clearly evident in all plants inoculated with Phaeoacremonium species and C. malorum. Decayed areas caused by F. mediterranea were observed only in some potted plants either 15 or 18 months after inoculation. Some of the vines inoculated with P. aleophilum, C. malorum and F. mediterranea shrivelled up completely. Inoculated fungi were always recovered from the discoloured and decayed tissue. Both types of wood deterioration observed in the field on diseased plants were reproduced in the pathogenicity tests.