Treatment solutions to cure Xylella fastidiosa diseased plants

Tabs

Article
CoDiRO strain, copper, olive disease management, symptom expression, zinc
First published in the EFSA Journal
20 aprile 2016
Adopted
5 aprile 2016
Type
Statement
Abstract
This opinion addresses the question of the efficacy of current treatment solutions to cure Xylella fastidiosa diseased plants, and discusses the experimental treatments under evaluation by two research groups in Apulian olive orchards infected by strain CoDiRO (Complesso del Disseccamento Rapido dell’Olivo). The increasing problems from newly emerging vascular bacterial diseases and the limited success to cure plants from such infections have stimulated numerous studies on treatments with chemical and biological compounds. Under field conditions, various formulations of copper and zinc as spray or root drench are currently used while further options, for example the application of bioactive substances, are at an experimental stage. In Apulia, preliminary results from intensive treatments with such formulations, in combination with the use of good crop management practices, reported more vigorous new growth of diseased trees. However, results provided so far confirmed the continued presence of X. fastidiosa after the treatments under evaluation. This is in agreement with current knowledge that there are no means to cure plants from this bacterial disease, in the sense of eliminating the pathogen from plant tissues. The reported positive response of the treated olive trees is most probably due to the effect of micronutrients and other bioactive compounds that, together with soil cultivation and agronomical practices, improve the vigour of the plants and their resilience to stress caused by bacterial infections. Notwithstanding the preliminary status of these findings, the Panel acknowledged the potentially positive effects of such treatments in prolonging the productive phase of olive trees and their putative relevance for the management of olive orchards, particularly in the containment area where eradication of the pathogen is considered no longer possible. The Panel also concluded that long-term studies are needed to confirm that the reported positive effects on crop performance can be sustained over many years.
Panel members at the time of adoption
Claude Bragard, David Caffier, Thierry Candresse, Elisavet Chatzivassiliou, Katharina Dehnen-Schmutz, Gianni Gilioli, Jean-Claude Gregoire, Josep Anton Jaques Miret, Michael Jeger, Alan MacLeod, Maria Navajas Navarro, Bjoern Niere, Stephen Parnell, Roel Potting, Trond Rafoss, Vittorio Rossi, Gregor Urek, Ariena Van Bruggen, Wopke Van Der Werf, Jonathan West and Stephan Winter
Panel on Plant Health
Contact
alpha [at] efsa.europa.eu
doi
10.2903/j.efsa.2016.4456
EFSA Journal 2016;14(4):4456 [12 pp.].
Question Number
On request from
European Commission
Print on demand
Number of Pages
12