Detection of Cucurbit Viruses in New Jersey. Robert F. Davis, Assistant Professor, Department of Plant Pathology, Cook College, New Jersey Agricultural Experiment Station, New Brunswick 08903. M. K. Mizuki, Visiting Fellow, Department of Plant Pathology, Cook College, New Jersey Agricultural Experiment Station, New Brunswick 08903. Plant Dis. 71:40-44. Accepted for publication 10 September 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0040.

During a 3-yr study of virus diseases of cucurbits in New Jersey, we found that different viruses were associated with severe disease symptoms, depending on the year. In 1983, cucumber mosaic virus (CMV) caused the most severe disease in squash (Cucurbita pepo) although watermelon mosaic virus 2 (WMV-2) was the most prevalent. In 1984, the watermelon mosaic strain of papaya ringspot virus (PRSV-W) caused a destructive disease of squash. Zucchini yellow mosaic virus (ZYMV) was detected for the first time in New Jersey in 1985 and caused severe losses in squash and other cucurbit crops. In field samples infected with various mixtures of ZYMV, WMV-2, and PRSV-W, ZYMV usually predominated after rub-inoculation of susceptible test plants and detection by enzyme-linked immunosorbent assay (ELISA). ELISA of field samples was thus more reliable as an indication of the viruses present in such samples than ELISA of experimental test plants rub-inoculated with sap from field samples. ZYMV is highly aggressive and appears to have a competitive advantage over PRSV-W and WMV-2 in mixed infections. Most ZYMV isolates occurring in New Jersey were similar to the Connecticut strain (ZYMV-CT); however, one isolate of ZYMV from zucchini, designated ZYMV-NJ_sn, unique from previously reported isolates in its ability to induce severe stunting and necrosis in squash, represents another biotype of ZYMV.