Is Roesleria subterranea a primary pathogen or a minor parasite of grapevines? Risk assessment and a diagnostic decision scheme

Abstract

In the past the root rot pathogen Roesleria subterranea (Ascomycota) was generally considered as a minor parasite, a view with which we were often confronted during field work in German winegrowing regions where this ascomycete recently caused serious problems in established vineyards and at replant sites. To irrevocably demonstrate that R. subterranea is not a minor, but a primary pathogen of grapevines (and fruit trees) a pest risk analysis was carried out according to the guidelines defined by EPPO standard series PM 5, which defines the information needed, and contains standardised, detailed key questions and a decision support scheme for risk analysis. Following the provided decision scheme, it becomes apparent that R. subterranea must be considered as a serious, primary pathogen for grapevines and fruit trees that can cause massive economic losses. Based on the literature, the pathogen seems to be ubiquitous in wine growing regions in cool climates of the northern hemisphere. It is likely that because of its growth below ground, the small fruiting bodies, and ambiguous symptoms above ground, R. subterranea has been overlooked in the past and therefore, has not been considered as primary pathogen for grapevine. Available published information together with experience from field trials was implemented into a diagnostic decision scheme which will, together with the comprehensive literature provided, be the basis (a) to implement quick and efficient diagnosis of this pathogen in the field and (b) to conduct risk analysis and management in areas where R. subterranea has not established yet.

Soil Microbial Community Composition and Diversity Remained Unchanged in a Semiarid Grassland in Northwestern China After 7 Years of Nitrogen Addition

“…This observation is consistent with the prediction of copiotrophic hypothesis (Li et al 2015). The species of two genera, Periconia, and Roesleria whose relative abundance increased signi cantly with increasing N inputs were considered plant-pathogenic fungi (Neuhauser et al 2011; Markovskaja and Kačergius 2014), indicating that N addition can increase the risk of plant diseases. The high rates of OTUs immigration and extinction, and the low relative abundance of OTUs suggest that N addition may have caused changes in rare taxa rather than common taxa.…”

Demystifying biotrophs: FISHing for mRNAs to decipher plant and algal pathogen–host interaction at the single cell level

“…Plasmodiophora brassicae , the clubroot pathogen, causing a loss of roughly 10% of the world brassica crop production 20 . Additionally, ten phytomyxid species parasitize important marine primary producers, namely brown algae, seagrasses and diatoms, with essentially unknown ecological consequences 21 , 22 . In brown algae, the galls formed by Maullinia braseltonii on the Pacific bull kelp ( Durvillea antartica ) affect the commercial value of this locally important food source.…”

Rediscovery of Roesleria subterranea from Japan with a discussion of its infraspecific relationships detected using molecular analysis

“…Yao and Spooner (1999) proposed Roesleriaceae, but its placement was not mentioned by Kirk et al (2008). Based on the molecular phylogeny on rDNA, it was classified as Helotiaceae, but Roesleriaceae as a distinct family has not been ruled out (Kirchmair et al 2008, Neuhauser et al 2011.…”

“…Redhead is a distinctive hypogeous fungus currently placed in Roesleriaceae (Yao and Spooner 1999) or Helotiaceae Helotiales (Neuhauser et al 2011). It is recognized as a facultative root parasite that causes damage to grape vines (Neuhauser et al 2011).…”