Phellinus Species Inducing Hoja de Malvón Symptoms on Leaves and Wood Decay in Mature Field-Grown Grapevines

Abstract

Hoja de malvón is a common vine wood disease widely spread in grape production areas of Argentina
which causes wood necrosis, decline, and the death of plants. Leaves are smaller than normal and chlorotic, with
margins curled downwards. A basidiomycete, provisionally classified as Phellinus sp., is the fungus most frequently
isolated from infected plants. The aim of this study was to determine the pathogenicity of this fungus in field-grown
grapevines and to clarify its taxonomic positioning. The trunks and branches of five 13-year-old grapevines cv. Riesling
were infected on October 1994. Six years later some of the infected grapevines showed foliar symptoms of hoja de
malvón. The inoculated fungus was reisolated with relatively high frequency, together with other fungi from different
necrotic areas near the inoculation sites. The fungus under study was ascertained to belong to the Hymenochaetaceae
family (Aphyllophorales, Basidiomycota). Further inoculations of a much greater number of plants and with various
associated fungi like species of the genera Phaeoacremonium, Phaeomoniella and Botryosphaeria, will be conducted.