New plant pathogens reported in Greece from 1990 to 2007
New plant pathogens which have been recorded for the first time in Greece during the period 1990-2007 are presented in a review paper by Elena et al. (2008). Information was based on data published in Greek and international literature. During this period, 47 new plant pathogenic fungi have been reported in Greece, most of them causing damage to cultivated plants or forest trees (only a few of them seem to have a negligible effect). 5 bacteria have newly been reported, all were found on horticultural crops. 52 new viruses and viroids have been reported in Greece and characterized; 9 of them were considered to present the most serious threats affecting important crops such as citrus, tomato, cucumber and potatoes. It is noted that most pathogens described in this review paper result from survey work which was initiated to determine the sanitary situation of vegetatively propagated crops (e.g. fruit trees, grapevine, garlic, onions, orchids). It is also stressed that molecular methods have greatly contributed to the identification and characterization of pathogens, in particular of viruses and viroids. Finally, eradication, application of strict phytosanitary measures and use of virus-free propagation material are keys aspects in the control of these newly introduced pathogens. The EPPO Secretariat has extracted the following data concerning regulated pests:
- Fungi
Ceratocystis fimbriata f.sp. platani (EPPO A2 List): as reported earlier (EPPO RS 2004/009, 2007/189), this pathogen has a serious impact on the natural populations of Platanus orientalis in a small area of Southwestern Peloponnese.
Plasmopara halstedii *(EU Annexes): sunflower downy mildew was reported in 1991 in Thrace, Northern Greece.
- Viruses
Cherry necrotic rusty mottle virus* (CNRMV, formerly EPPO A2 List) and Little cherry virus;1* (Closterovirus, LChV1, EU Annexes) were both detected during a small scale survey of cherry trees (Prunus avium) carried out in 3 counties of Northern Greece (Piera, Pella, Imathia). Both viruses were found at high incidence (36% for CNRMV and 32% for LChV1).
Citrus tristeza virus (Closterovirus, CTV – EPPO A2 List): the presence of CTV was confirmed in 2000 on a sweet orange tree (Citrus sinensis cv. Lane Late) grafted on Carrizo citrange in Argolis county, Peloponnese (EPPO RS 2002/053). This tree belonged to a lot of 20 trees which had been illegally introduced from Spain in 1994. Phytosanitary measures were taken and the disease is thought to have been eradicated in Argolis. However, in Crete, the other region which had accepted the same infected material, the situation is more critical because CTV has been identified in Chania (where plant material was originally introduced) as well as in Rethymnon and Heraklion prefectures. More than 4000 trees have been destroyed so far. In addition, CTV has recently been detected in orange trees in the Arta valley (Northwestern Greece) and in clementine trees (C. clementina cv. Clemenpons) in Skala Lakonias (Southern Peloponnese) which had been imported from Spain. It is considered that the situation is rendered more critical with the recent introduction of Toxoptera citricida in Spain and Portugal, and that strict phytosanitary measures should be imposed.
Tomato yellow leaf curl virus (Begomovirus, TYLCV - EPPO A2 List): TYLCV was first detected in 2000 in Crete (Ierapetra, Tympaki) and Southern Peloponnese (Lakonia) on glasshouse tomatoes (see also EPPO RS 2001/107). Since then, the virus has become endemic in these regions and has been detected in others (Preveza, Karditsa). In 2005, a new outbreak of tomato yellow leaf curl disease occurred in Crete, Southern Peloponnese and Rhodos Island. Molecular analysis revealed the presence of a second virus species Tomato yellow leaf curl Sardinia virus (Begomovirus, TYLCSV - EPPO A2 List) in Crete and Peloponnese (EPPO RS 2007/055). Both species are commonly found in mixed infections. In 2007, the presence of TYLCV was reported on common bean (Phaseolus vulgaris) growing in the vicinity of infected tomatoes.
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* New record according to the EPPO Secretariat.
Sources
Elena K, Alivizatos AS, Varveri C (2008) New plant pathogens reported in Greece, 1990-2007. Hellenic Plant Protection Journal 1(1), 1-25.