SENSITIVITY OF ENRICHMENT ISOLATION FOR FIRE BLIGHT DETECTION IN COMPOSITE TWIG SAMPLES

Fire blight testing of asymptomatic samples serves several purposes, e.g., (i) checking for occurrence of the disease in uninfected areas, (ii) checking for occurrence of the disease in buffer zones surrounding places of propagating material production inside infected areas and (iii) as a technical support to delineation of areas with “zona protecta” status, officially recognized as disease free.
Countries have different approaches to testing asymptomatic samples, yet sampling is still recognized as the biggest source of uncertainty.
A survey, recently conducted by the European and Mediterranean Plant Protection Organization (EPPO) showed that laboratories test single twigs or composite samples of up to 30 twigs.
Here we report on the analytical sensitivity of enrichment isolation when testing single (one twig) and composite samples (10 or 30 twigs) with defined starting concentrations of Erwinia amylovora ranging from 10⁶ to 1 CFU/ml.
Under our experimental conditions a low analytical sensitivity of enrichment isolation on CCT media was observed irrespective of background matrix, i.e., single twigs, 10 or 30 twigs.

XIII International Workshop on Fire Blight

M. Pirc, M. Ravnikar , T. Dreo

Erwinia amylovora, enrichment isolation, sensitivity, asymptomatic samples

https://doi.org/10.17660/ActaHortic.2014.1056.11