Viruses occurring in onion crop in amasya province, the major onion producing region in Turkey.

Amasya is the greatest onion producing area in Turkey. Onion fields from Amasya region were surveyed for virus diseases in 2009-2011 and tested for the presence of the most important onion viruses such as Onion yellow dwarf virus (OYDV), Iris yellow spot virus (IYSV), Leek yellow stripe virus (LYSV), Shallot latent virus (SLV) and Garlic common latent virus (GCLV). The presence of virus diseases and their identification was ascertained through symptom observation in the fields, sap transmission to hosts, and DAS-ELISA. Based on the ELSA results, 57 out of 332 samples (17.16 %) were infected with viruses. The results showed that the highest infection was caused by OYDV (12.33 %) followed by LYSV (3.60 %). Only 1.19 % of the samples were infected with SLV, but none of the samples were found to be infected for GCLV and IYSV.