Localized Distribution of Iris yellow spot virus Within Leeks and Its Reliable Large-Scale Detection.

In a survey to determine the incidence of Iris yellow spot virus (IYSV) in crops of several host species, samples of one leaf tip/plant were collected at random. When tested by enzyme-linked immunosorbent assay (ELISA) using IYSV-specific antibodies and a blocking step that improved test reliability, the virus was detected only in leek and onion. It was found in 11 of 21 leek and 2 of 26 onion plantings with apparent incidences of 1 to 7 and 1%, respectively.