TreeBASE Search-Trees for study 16794

@ARTICLE{TreeBASE2Ref23984, author = {Netsai M. Machingambi and Leanne L. Dreyer and Kenneth Carl Oberlander and Jolanda Roux and Francois Roets}, title = {Death of endemic Virgilia oroboides trees in a South African national botanical garden caused by Diaporthe virgiliae sp. nov. }, year = {2014}, keywords = {root pathogen, tree death, Phomopsis, Geosmithia, bark beetle}, doi = {}, url = {http://}, pmid = {}, journal = {Plant Pathology}, volume = {}, number = {}, pages = {}, abstract = {Numerous dead and dying individuals of the Western Cape endemic tree Virgilia oroboides (Fabaceae) were recently observed within a South African national botanical garden. Root-rot fungi and bark beetle (Curculionidae; Scolytinae) symbiotic fungi from diseased trees were assessed for their respective roles in V. oroboides mortality. Disease progression in this V. oroboides population was also monitored over one year. Fungi were isolated from surface sterilised bark and root samples from diseased trees and were provisionally identified using data from the internal transcribed spacer regions (ITS1, ITS2), including the 5.8S gene (ITS). Pathogenicity of selected fungi towards V. oroboides was tested using artificial inoculation studies under field conditions. The pathogenicity of various bark beetle associated Geosmithia (Hypocreales: Hypocreomycetidae) spp. from V. oroboides, were similarly assessed. The only fungus consistently isolated from lesions on the roots and bark of declining V. oroboides, and never from healthy individuals, represented an un-described Diaporthe (Diaporthales, Diaporthaceae) sp. that was characterised using molecular - (using data from the ITS marker and part of the β-tubulin gene (TUB)), culture and morphological characters. It is an aggressive pathogen of V. oroboides, newly described here as Diaporthe virgiliae sp. nov. Trees of all ages are susceptible to this pathogen with subsequent bark beetle attack of mature trees only. All Geosmithia spp. were non-pathogenic towards V. oroboides. Diaporthe virgiliae caused a significant decline in the health of the monitored V. oroboides population over a period of only one year and should be considered as a significant threat to these trees. } }