Characterization of a Potexvirus Isolated from Night-Blooming Cactus. A. E.- S. A. Fudl-Allah, Department of Plant Pathology, University of California, Riverside 92521. L. G. Weathers, and F. C. Greer, Jr., Department of Plant Pathology, University of California, Riverside 92521. Plant Dis. 67:438-440. Accepted for publication 18 November 1982. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-438.

Plants of night-blooming cactus Hylocereus undatus as well as scions of several species of cactus grafted to it were stunted, malformed, and systemically mottled. A flexuous virus averaging 515 nm long was isolated from the affected plants. The virus was sap-transmitted to a limited number of hosts. Symptoms in Chenopodium quinoa consisted of chlorotic primary lesions and systemic mottle and necrosis. Gomphrena globosa and Amaranthus caudatus showed primary local lesions. Plants of Saponaria vaccaria showed only systemic mottling. Crystalline inclusions were found by light microscopy in epidermal cells of infected H. undatus. The virus had a thermal inactivation point above 95 C and a dilution end point of 10⁶–10⁷ in sap from infected C. quinoa. The virus reacted with antisera prepared against California barrel cactus and Chessin's isolate of cactus virus X.