VIEW ARTICLE

Etiology

Association of Bacterialike Organisms With a New Potato Disease. M. Klein, Department of Entomology, The Hebrew University of Jerusalem, Faculty of Agriculture, Rehovot, The Volcani Center, Bet Dagan, Israel; Sara Zimmerman-Gries(2), and B. Sneh(3). (2)Virus Laboratory, Agricultural Research Organization, The Volcani Center, Bet Dagan, The Volcani Center, Bet Dagan, Israel; (3)Department of Phytopathology, The Volcani Center, Bet Dagan, Israel. Present address of junior author: Michigan State University, Department of Botany and Plant Pathology, East Lansing 48824, U.S.A. Phytopathology 66:564-569. Accepted for publication 15 December 1975. DOI: 10.1094/Phyto-66-564.

A new disease of potatoes, termed leaflet stunt, is described. The disease, which has so far been found only in Israel, is characterized mainly by deformation and stunting of leaflets. Bacterialike bodies were found only in phloem cells of infected plants, but not in healthy plants. Each body is bounded by two sets of membranes. In transverse section these bodies have a spherical shape, but when sectioned longitudinally rod-shaped particles measuring 1.0-2.40 × 0.2 - 0.3 µm are discerned. Beaded forms enclosed by a plasma membrane are sometimes detected inside the particle. Unlike most bacterialike organisms recently claimed to cause yellows type diseases in trees or grape-vines, the outer membranous wall of the organism found in phloem cells of infected potatoes is generally thin and unrippled. According to its ultrastructure, the organism found in infected potatoes resembles the clover-club leaf pathogen rather than those of four other plant diseases, in which xylem but not phloem tissues are claimed to be inhabited by the suspected causal organisms.