Incidence of viruses and virus-like diseases of watermelons and pumpkins in Uganda, a hitherto none investigated pathosystem
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Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
African Journal of Agricultural Research
Abstract
Common impromptu observations between 2010 and 2012 of apparent virus-like disease symptoms in
watermelons and pumpkins in Uganda prompted this study. However, there was no recorded evidence
of virus infection in these crops anywhere in Uganda or eastern Africa as a region. Thus, 374 and 522
watermelon and pumpkin plants, respectively, growing in 13 fields were surveyed to record virus-like
disease symptoms in Uganda’s four districts of Mbale and Kamuli (eastern region), Mpigi and Masaka
(central region) during August to November 2013, and January to March 2014. Leaf samples were also
collected and tested for four viruses known to commonly infect watermelons and pumpkins worldwide.
Symptom severity was assessed using a scale of 0 to 5, while virus incidence was determined by
serological methods. The four viruses tested were Cucumber mosaic virus (CMV), Watermelon mosaic
virus (WMV), Zucchini yellow mosaic virus (ZYMV) and Cucurbit aphid borne-yellows virus (CABYV). In
both crops, there was a higher incidence of virus-like diseases in central than in eastern region (P =
0.000). All the four viruses were detected with CMV as the most common, followed by WMV, ZYMV, and
CABYV. Differences in virus incidences between the districts were not always significant. Single CMV,
dual CMV+WMV and triple CMV+WMV+ZYMV were the most common single, and multiple infections in
both crops. Watermelons contained more single virus infections than mixed infections (P < 0.001), but
this difference was not significant in pumpkins (P = 0.468). In all, single virus infections were
significantly higher in watermelons than pumpkins (P < 0.001). This is the first study to report incidence
of viruses and virus-like diseases in watermelons and pumpkins in Uganda, and in eastern Africa as a
region. The importance of these results with respect to crop production and next steps in virus disease
management are discussed.
Description
Keywords
Cucurbits, DAS-ELISA, Multiple virus infection, TAS-ELISA, Virus incidence, Uganda
Citation
Masika, F. B., Kisekka, R., Alicai, T., & Tugume, A. K. (2017). Incidence of viruses and virus-like diseases of watermelons and pumpkins in Uganda, a hitherto none-investigated pathosystem. African Journal of Agricultural Research, 12(3), 177-191. DOI: 10.5897/AJAR2016.11463