VIEW ARTICLE

Vector Relations

Transmission of Spiroplasma citri from Citrus to Citrus by Scaphytopius nitridus. G. N. Oldfield, Research Entomologist, Agricultural Research Service, U.S. Department of Agriculture, Western Region, Boyden Entomology Laboratory, Riverside, CA 92502; G. H. Kaloostian(2), H. D. Pierce(3), E. C. Calavan(4), A. L. Granett(5), R. L. Blue(6), G. L. Rana(7), and D. J. Gumpf(8). (2)(3)Research Leader, and Agricultural Research Technician, respectively, Agricultural Research Service, U.S. Department of Agriculture, Western Region, Boyden Entomology Laboratory, Riverside, CA 92502; (4)(5)(6)(7)(8)Professor and Plant Pathologist, Postgraduate Research Plant Pathologist, Staff Research Associate, Research Associate and Plant Pathologist (from the Department of Plant Pathology, University of Bari, Bari, Italy), and Assistant Professor and Plant Pathologist, respectively, Department of Plant Pathology, University of California, Riverside, CA 92502. Phytopathology 67:763-765. Accepted for publication 17 December 1976. Copyright © 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-763.

Laboratory-reared Scaphytopius nitridus, a leafhopper that reproduces on citrus in southern California, transmitted Spiroplasma citri from stubborn-diseased citrus to healthy sweet orange seedlings. Transmission occurred after leafhoppers were fed either 3 wk on a source plant, or 5 days on a source plant, then 16 days on celery. After either feeding regimen, transmission to healthy citrus occurred very infrequently when plants were exposed to 15 insects each. Transmission occurred more frequently when S. nitridus were fed 3 wk on the source plant and then were given access to healthy sweet orange seedlings at the rate of 100/plant. Sweet orange seedlings exposed only to S. nitridus (15/ plant and 100/plant) that had fed only on celery or healthy citrus did not develop stubborn, nor did several hundred other such seedlings that were not exposed to S. nitridus.