An unknown trees die back caused by Pseudomonas species in Switzerland

Autorzy

• François Lefort University of Applied Sciences and Arts Western Switzerland, Geneva Institute for Technology Architecture and Landscape, Institute Land Nature and Environment, Plants and Pathogens Group,
  50 route de Presinge, 1254 Jussy, Switzerland
  e-mail: francois.lefort@hesge.ch
• Julien Crovadore University of Applied Sciences and Arts Western Switzerland, Geneva Institute for Technology Architecture and Landscape, Institute Land Nature and Environment, Plants and Pathogens Group,
  50 route de Presinge, 1254 Jussy, Switzerland
• Romain Gilodi Plants and Pathogens Group, Institute Earth Nature and Landscape, Geneva Institute of Engineering, Architecture and Landscape, University of Applied Sciences of Western Switzerland
  150 route de Presinge, 1254 Jussy, Switzerland
• Gautier Calmin Plants and Pathogens Group, Institute Earth Nature and Landscape, Geneva Institute of Engineering, Architecture and Landscape, University of Applied Sciences of Western Switzerland
  150 route de Presinge, 1254 Jussy, Switzerland
• Tomasz Oszako Department of Forest Pathology, Forest Research Institute
  Braci Leśnej Street 3, Sękocin Stary, 05– 090 Raszyn, Poland
• Justyna A. Justyna A. Nowakowska Department of Forest Genetics and Tree Physiology, Forest Research Institute
  Braci Leśnej Street 3, Sękocin Stary, 05–090 Raszyn, Poland

Abstract

A model for tree pathogen diagnosis – Prunus domestica L. has been studied against pathogenic bacteria. An orchard of 110 trees of P. domestica showed dying back symptoms in May 2009 and nineteen of these trees were eradicated and burnt for prophylaxis. No symptoms correlated with those caused by pathogens previously observed in stone fruit die back in Europe or elsewhere (Pseudomonas syringae pv syringae van Hall, Pseudomonas syringae pv morsprunorum Lazarowtz, Phytophthora sp., Diaporthe perniciosa Marchal., phytoplasma or viruses) were not found. Interestingly, cutting the trunk in transversal sections allowed the observation of stem heart necrosis which was mostly important at the grafting point. Isolations from necrotic stem heart allowed to identify anot yet described Pseudomonas species not related to P. syringae. The method described in the paper for isolation of pathogenic bacteria and their quick an reliable identification can be also applied for detection of pathogens in forest tree plantations.

Keywords

• PCR and sequencing diagnostic
• Prunus domestica
• Pseudomonas
• rootstock
• stone fruit die back