Effect of Citrus Exocortis Viroid on Flower and Fruit Structure and Development on Etrog Citron. W. P. Bitters, Horticulturist Emeritus, University of California, Riverside 92521. N. Duran-Vila, and J. S. Semancik. IVIA, Moncada (Valencia), Spain; and Plant Pathologist, University of California, Riverside 92521. Plant Dis. 71:397-399. Accepted for publication 28 October 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0397.

Rooted cuttings of Etrog citron (Citrus medica) were inoculated with the citrus exocortis viroid (CEV). Typical exocortis symptoms were expressed in these plants within 2 mo. Affected plants were retained after the initial foliage symptoms for between 2.5 and 3 yr, which provided an opportunity for the plants to flower and set fruit. Floral morphology was abnormal from that of healthy plants in that the corolla failed to open. Fruits that developed from these flowers were characterized by a ringed constriction resembling an asymmetrical “hourglass” that contained a high percentage of seeds that aborted and lacked viability. S-1 citron cuttings inoculated with the citron variable viroid (CVaV) did not produce these types of symptoms, which therefore might be considered characteristic of severe CEV infection.