Occurrence Of Viruses Infecting Watermelon, Other Cucurbits, and Weeds in the Parts of Southern United States

Abstract

Field surveys were conducted to determine the distribution and frequency of viruses infecting watermelon and other cucurbits in the southern US in 2010 and 2011. Leaf samples were collected from 715 symptomatic plants from 10 states and were tested by dot-immunobinding assays or reverse transcriptionpolymerase chain reaction for 17 viruses that included Alfalfa mosaic virus (AMV), Bean pod mottle virus (BPMV), Cucurbit aphid born yellows virus (CABYV), Cucurbit yellow stunting disorder virus (CYSDV), Cucumber green mottle mosaic virus (CGMMV), Cucumber mosaic virus (CMV), Melon necrotic spot virus (MNSV), Papaya ringspot virus-W (PRSV-W), Squash leaf curl virus (SLCuV), Soybean mosaic virus (SMV), Squash mosaic virus (SqMV), Squash vein yellowing virus (SqVYV), Tobacco ringspot virus (TRSV), Watermelon mosaic virus (WMV), Watermelon silver mottle virus (WSMoV), Zucchini yellow mosaic virus (ZYMV), and Zucchini green mottle mosaic virus (ZGMMV). Thirteen out of 17 viruses were detected in this study. The distribution of detected viruses varied with the highest average frequency for WMV (30.6%), followed by PRSV-W (24.7%), ZYMV (13.9%), TRSV (5.7%), SqMV (3.5%), and MNSV (2.6%). The percent frequency of the remaining viruses was less than 2%. Seven viruses (AMV, BPMV, CMV, SqMV, TRSV, PRSV-W, and ZYMV) were also detected either from nearby agricultural crops or weeds species. Mixed infections were also recorded for some viruses with potyviruses being the most common. There is limited information on frequency and distribution of viruses that occur on watermelon and other cucurbits. These results indicate that potyviruses, particularly PRSV-W, WMV, and ZYMV, are frequently present in infected watermelon and other cucurbits in the southern US. Accepted for publication 30 July 2012. Published 24 August 2012.