VIEW ARTICLE

Particle Numbers Associated with Mechanical and Aphid Transmission of Some Plant Viruses. H. L. Walker, Department of Plant Pathology, University of Kentucky, Lexington 40506; T. P. Pirone, Department of Plant Pathology, University of Kentucky, Lexington 40506. Phytopathology 62:1283-1288. Accepted for publication 18 May 1972. DOI: 10.1094/Phyto-62-1283.

Manual inoculation of leaves of Chenopodium amaranticolor resulted in the production of one local lesion for every 10⁷ cucumber mosaic virus (CMV) or tobacco etch virus (TEV) particles, for every 3 × 10⁶ cowpea chlorotic mottle virus particles, and for every 10⁵ tobacco mosaic virus particles in the inoculum. Systemic infection of tobacco plants with CMV was obtained with manually applied inoculum which contained 10⁷ particles, but not with inoculum which contained 10⁶ particles. Aphids could consistently transmit, to tobacco plants, CMV acquired from solutions which contained 7 × 10¹² virus particles/ml and occasionally from solutions which contained 7 × 10¹¹ particles/ml. The volume of liquid associated with the stylets of an aphid was determined to be between 0.6 and 4.2 × 10^–10 ml. Based on a CMV concentration of 7 × 10¹² particles/ml, about 1,000 virus particles would be present in this volume. A method is described for purification of TEV which yields unaggregated virus suitable for particle counts.