Cucurbit Genetics Cooperative Report 7:78-79 (article
Epidemics of Zucchini Yellow Mosaic Virus and Other Cucurbit
Viruses in Egypt in the Spring of 1983
New York State Agricultural Experiment Station, Cornell
University, Geneva, NY 14456
Cornell University, Ithaca, NY 14853
University of California, Riverside, CA 92521
In Egypt, during the spring of 1983, viral diseases were
responsible for devastating epidemics in cucumber, melon, squash
and watermelon fields. Our surveys, which were conducted in May,
included experimental and commercial fields in the Delta, along
the Nile River, from Cairo to Sids, Ismailia (Suez Canal) and an
agricultural development project in the Sinai.
Particularly affected were cultivars of summer squash (Cucurbita pepo L.), which reacted to viral infection with
plant stunting, severe foliar symptoms and distorted fruits.
These malformed fruits were frequently sold in local markets. In
fields where viral infection had occurred in an early stage of
plant growth, production was totally lost, since fruits either
aborted or remained very small.
Because of the similarity in symptomatology, it was often
difficult to differentiate plants infected with watermelon mosaic
virus 1 (WMV-1) from those infected with zucchini yellow mosaic
virus (ZYMV). Both of these viruses caused very severe foliage
mosaic and knobbed fruits, and they appear to be the most
prevalent and widespread. WMV-1 and ZYMV were followed in order
of importance, by cucumber mosaic virus (CMV) and watermelon
mosaic virus 2 (WMV-2). Squash mosaic virus (SqMV) was confined
to isolated melon and squash plants, and its spread was impaired
by low beetle populations. Conversely, CMV, WMV-1, WMV-2 and
ZYMV were spread efficiently by several aphid species.
The presence of ZYMV in Egypt and of the other viruses was
confirmed by the analysis of infected specimens. The
identification was accomplished using electron microscopy,
serology and diagnostic hosts. The Egyptian isolates of ZYMV
incited symptoms closely resembling those caused by European
isolates of this virus (1,3) and the American strain, ZYMV-CT
In Egypt, a good control of these viral diseases was achieved
when plants were grown initially under low plastic tunnels. When
the plastic was removed to facilitate pollination, plants
appeared to be healthy and produced a good crop. However,
without the protective plastic shield, which had interfered with
the activity of the vectors, these plants eventually succumbed to
Plastic tunneling obviously adds to the production cost, but it
offers an alternative to the total loss of the crop, particularly
in years of devastating epidemics.
In addition to Egypt, ZYMV has been found in France, Germany,
Israel, Italy, Morocco, Spain (2) and the USA (4,5).
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