A severe yellow and leaf curl disease affecting field squash was found
in the Batinah region of the Sultanate of Oman. The symptoms appear a
s small yellow spots, diffuse veinal yellowing, and leaf curling of yo
ung leaves. The inciting virus was easily transmitted by mechanical in
oculation and by the whitefly Bemisia tabaci in a semi-persistent mann
er. The host range of the virus was restricted to two cucurbit species
. Leaf dip preparations contained few flexuous particles about 700 to
750 nm long. Pinwheel-like inclusion bodies were observed in thin sect
ions of diseased squash tissues. Serological tests by enzyme-linked im
munosorbent assay showed that the virus is serologically related to wa
termelon mosaic virus-2, but not to zucchini yellow mosaic virus or pa
paya ring spot virus (watermelon strain). In view of these properties,
this virus is considered to be a newly described virus and is tentati
vely named squash yellow leaf curl virus.