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Etiology

Partial Characterization of a Potyvirus Infecting the Milkweed Vine, Morrenia odorata. R. Charudattan, Associate professor, Department of Plant Pathology, University of Florida, Gainesville, 32611; F. W. Zettler(2), H. A. Cordo(3), and R. G. Christie(4). (2)Professor, Department of Plant Pathology, University of Florida, Gainesville, 32611; (3)Official-in-charge, USDA-SEA-AR, Biological Control of Weeds Laboratory, Hurlingham, Buenos Aires, Argentina; (4)Plant Pathologist III, Department of Agronomy, University of Florida. Phytopathology 70:909-913. Accepted for publication 15 March 1980. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1980. DOI: 10.1094/Phyto-70-909.

A previously undescribed potyvirus was detected in plants of two Araujia spp. and two Morrenia spp. growing in Argentina. An isolate of cucumber mosaic virus, but not the potyvirus, was detected in M. odorata in Florida. The potyvirus infected manually inoculated plants representing six genera in the Asclepiadaceae (Araujia, Cynanchum, Hoya, Matelea, Morrenia, and Sarcostemma), but not 150 host cultivars representing 108 species of 75 genera in 25 plant families. Of 115 particles measured in negatively stained leaf extracts of M. odorata, 92.2% were between 680 and 801 nm in length with a main maximum at 741 nm. Thin sections of infected leaves revealed cylindrical inclusions characteristic of potyviruses. The virus was transmitted in a stylet-borne manner to M. odorata by individuals of Aphis nerii, A. spiraecola, and Myzus persicae. No serological relationships were established in immunodiffusion tests between antigens of the virus and antisera to 13 other potyviruses. The virus had a dilution end point that ranged 1 × 10^–2 – 1 × 10^–3, longevity in vitro of 48–60 hr, and thermal inactivation point of 56–58 C. The virus appears to be a safe and promising biocontrol agent for the milkweed vine (M. odorata) in Florida citrus groves.