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Mycoplasmalike Bodies in Periwinkle: Their Cytology and Transmission by Pear Psylla from Pear Trees Affected with Pear Decline. G. H. Kaloostian, Investigations Leader, Entomology Research Division, ARS, USDA, Riverside, California 92502; H. Hibino(2), and H. Schneider(3). (2)(3)Visiting Assistant Plant Pathologist and Plant Pathologist, respectively, Department of Plant Pathology, University of California, Riverside 92502. Phytopathology 61:1177-1179. Accepted for publication 5 May 1971. DOI: 10.1094/Phyto-61-1177.

In three experiments, mycoplasmalike bodies were transmitted from pear trees, Pyrus communis, with the symptoms of pear decline disease, to 40-50% of test periwinkle plants (Vinca rosea) by pear psylla (Psylla pyricola). All 12 control plants (exposed to pear psylla collected from disease-free trees) remained healthy. Mycoplasmalike bodies were present in the sieve tubes and phloem parenchyma cells of the two diseased plants examined, but were absent from plants fed on by pear psylla from healthy trees. These bodies were much like those found in plants infected with many yellows-type diseases: they had a unit membrane, ribosome-like particles, no vacuole, and a filamentous network.