Disease Note

Zucchini Yellow Mosaic Virus in Squash in Arkansas. S. L. Wickizer, Department of Plant Pathology, University of Arkansas, Fayetteville 72701. H. A. Scott, and J. M. McGuire, Department of Plant Pathology, University of Arkansas, Fayetteville 72701. Plant Dis. 70:78. Accepted for publication 16 September 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-78c.

A disease outbreak resulting in fruit malformation, discoloration, foliar distortion, and mosaic occurred in zucchini and yellow summer squash (Cucurbita pepo var. melopepo (L.) Alef.) in the Arkansas River valley in 1981. Watermelon mosaic viruses (WMV) 1 and 2 were primarily responsible for these symptoms. However, one virus isolate from zucchini squash, which did not react with antisera to WMV 1 and 2, was serologically identical to an Egyptian isolate of zucchini yellow mosaic virus (ZYMV) obtained from M. F. Ouf, University of Minia, Egypt, and identified by R. Provvidenti, Geneva, NY. This virus, ZYMV-AR, infected only inoculated leaves of Pisum sativum L. ‘Alaska,’ was systemic in Luffa acutangula Roxb. and nine other squash cultivars inoculated, did not infect Nicotiana benthamiana L. Domin., and was transmitted by Myzus persicae and Aphis fabae. The incidence of ZYMV-AR was minimal in Arkansas until 1985, when it was found to be widespread in watermelon (Citrullus lanatus (Thunb.) Mansf.) and zucchini squash.