INTERNATIONAL WORKING GROUP ON FRUIT TREE VIRUSES

The tables of laboratory assays, bioassays, and indicator hosts were last presented in Acta Horticulturae 550: 473-493, 2001. As a result of the discussions of the Fruit Tree Virus Working Group during the business meetings of the 1994 Rome, the 1997 Bethesda, and the 2000 Canterbury Symposia, only few modifications were made to the lists of woody and herbaceous indicators since the publication in Acta Horticulturae 309: 407-418, 1992. Changes decided at the 1997 Bethesda Symposium and published in Acta Horticulturae 472: 759-783, 1998, included a different layout of the approved herbaceous and woody indicators, and updated nomenclature and knowledge about the causal agents of diseases.
As there had been rapid progress in the development of polymerase chain reaction (PCR) based assays in the 1990’s, it was decided in 1997 to compile a new list of laboratory assays.
Each list for the individual pome and stone fruit species contained the previously approved ELISA tests and, in addition, nucleic acid based tests.
Due to the constant development in methodology and often the existence of different probes, primers and protocols, it was attempted to list only key references.
It was not feasible for the Fruit Tree Virus Working Group to compile detailed protocols.
The nucleic acid based assays previously suggested are mostly well adapted for equipped laboratories, however, in many cases, validation of the tests on a broader range of isolates was required.
This situation had not fundamentally changed at the 2000 Canterbury and the 2003 Valencia Symposia.
Therefore, the list of molecular assays and their references was only updated in some cases and expanded where tests for additional viruses, viroids and phytoplasma diseases had become available.
Some detailed comments on the potential of the PCR tests are listed under technical notes.