Citrus exocortis viroid (CEVd) and Citrus cachexia viroid (CCaVd) detection was improved by setting up a new biological indexing method and comparing different molecular assays (molecular hybridisation, RT-PCR, sPAGE). Selected CEVd and CCaVd - infected sources, previously tested by sPAGE, were inoculated to Etrog citron cuttings, treated for rooting and kept in plastic bag at 35°C. Plants showed Ieaf epinasty 20 days after inoculation and reacted positively to dot-blot tests. This method proved to be reliable, time and space saving, easy and low cost. Comparing molecular assays in field diagnosis, RT-PCR showed to be the most sensitive method for CEVd and CCaVd detection from January to June, while dot-blot, tissue print and sPAGE were limited by the low viroid concentration in winter months.
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May can be considered the best month for starting viroid field detection, under Apulia conditions. Moreover, flowers showed to be a promising explant for viroid mass detection, mainly by tissue print.
