Situation of Iris yellow spot virus in Serbia
In Serbia, an intensive survey was conducted from 2005 to 2007 to determine the occurrence and distribution of Iris yellow spot virus (Tospovirus, IYSV – EPPO Alert List) on ornamental plants and onion crops (Allium cepa) grown in 14 and 9 districts, respectively. In total, 1,574 samples were collected and tested by DAS-ELISA. IYSV was not detected in any of the 668 samples of ornamental plants collected in 2005 and 2006, as well as in the 516 samples of ornamentals imported in 2005. The virus was only detected in onion samples collected at two locations. IYSV was detected in symptomatic samples from an onion seed crop at Sirig (district of South Bačka - see EPPO RS 2008/164) and in asymptomatic samples collected from an onion bulb crop at Obrenovac (district of the City of Belgrade). In the seed crop (A. cepa cv. ‘Stuttgarter’), the disease was observed in July 2007 with a high incidence (approximately 80%) and was associated with a high population of Thrips tabaci. In the onion bulb crop at Obrenovac, only two infected onion plants (of unknown cultivar) could be observed in the field with a relatively low population of T. tabaci.
Finally, seed transmission studies were carried out in Serbia but no virus transmission could be demonstrated in 5 000 tested seeds originating from IYSV-infected onion crops. Phylogenetic studies showed that the Serbian isolates obtained from the onion seed crop and the bulb crop belonged to two distant clades.
Sources
Bulajić A. Djekić I, Jović J, Krnjajić S, Vučurović A, Krstić B (2009) Incidence and distribution of Iris yellow spot virus on onion in Serbia. Plant Disease 93(10), 976-982.