Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

False-negative isolations or absence of lesions may cause mis-diagnosis of diseased plants infected with Phytophthora cinnamomi

False-negative isolations or absence of lesions may cause mis-diagnosis of diseased plants... In a series of growth cabinet, glasshouse and field experiments, tissue samples from living clonal Eucalyptus marginata (jarřah) were incubated immediately after sampling on agar (NARPH) selective for Phytophthora. Phytophthora cinnamomi was recovered 3–6 months after inoculation from 50% of samples with lesions and 30% of symptomless samples. However, up to 11% of samples with and without lesions and from which P. cinnamomi was not initially isolated contained viable pathogen. This was shown by removing tissue which had not produced any growth of P. cinnamomi on NARPH plates, cutting it into smaller sections, washing in sterile deionised water repeatedly for 9 days, and replating. Plating stem or bark tissue directly onto NARPH produced false-negative results for nine P. cinnarnomi isolates and six jarrah clones. The behaviour of the pathogen indicates that it could be present as dormant structures, such as chlamydospores, that need to be induced to germinate. Alternatively, fungistatic compounds in the tissue needed to be removed to allow the pathogen to grow. These results have important implications for disease diagnosis and management, disease-free certification and quarantine clearance. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Australasian Plant Pathology Springer Journals

False-negative isolations or absence of lesions may cause mis-diagnosis of diseased plants infected with Phytophthora cinnamomi

Download PDF
6 pages

Loading next page...
 
/lp/springer-journals/false-negative-isolations-or-absence-of-lesions-may-cause-mis-p4tgnZr0Xk

References (26)

Publisher
Springer Journals
Copyright
Copyright © 2000 by Australasian Plant Pathology Society
Subject
Life Sciences; Plant Pathology; Plant Sciences; Agriculture; Entomology; Ecology
ISSN
0815-3191
eISSN
1448-6032
DOI
10.1071/AP00029
Publisher site
See Article on Publisher Site

Abstract

In a series of growth cabinet, glasshouse and field experiments, tissue samples from living clonal Eucalyptus marginata (jarřah) were incubated immediately after sampling on agar (NARPH) selective for Phytophthora. Phytophthora cinnamomi was recovered 3–6 months after inoculation from 50% of samples with lesions and 30% of symptomless samples. However, up to 11% of samples with and without lesions and from which P. cinnamomi was not initially isolated contained viable pathogen. This was shown by removing tissue which had not produced any growth of P. cinnamomi on NARPH plates, cutting it into smaller sections, washing in sterile deionised water repeatedly for 9 days, and replating. Plating stem or bark tissue directly onto NARPH produced false-negative results for nine P. cinnarnomi isolates and six jarrah clones. The behaviour of the pathogen indicates that it could be present as dormant structures, such as chlamydospores, that need to be induced to germinate. Alternatively, fungistatic compounds in the tissue needed to be removed to allow the pathogen to grow. These results have important implications for disease diagnosis and management, disease-free certification and quarantine clearance.

Journal

Australasian Plant Pathology – Springer Journals

Published: Jan 27, 2011

There are no references for this article.