VIEW ARTICLE

Vector Relations

Leafhopper Vectors of the Peach X-Disease Pathogen and Its Seasonal Transmission from Chokecherry. D. A. Rosenberger, Research Assistant, Department of Botany and Plant Pathology, Michigan State University, East Lansing, MI 48824, Senior author's present address: New York State Agricultural Experiment Station, Hudson Valley Research Laboratory, Highland, NY 12528; A. L. Jones, Professor, Department of Botany and Plant Pathology, Michigan State University, East Lansing, MI 48824. Phytopathology 68:782-790. Accepted for publication 31 October 1977. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-782.

The peach X-disease organism (XDO) was transmitted during June, July, and August to peach and chokecherry indicator plants exposed for 5-wk periods beside X-diseased chokecherry (Prunus virginiana) in the field. Twenty-six percent of 387 indicator plants exposed in 1974 developed X-disease symptoms compared to 5% of 359 plants exposed in 1975 and 3% of 273 plants exposed in 1976. Transmission to indicator plants could not be directly correlated with the numbers of Paraphlepsius irroratus, Scaphytopius acutus, and Colladonus clitellarius vectors captured on sticky-boards at the exposure sites. Paraphlepsius irroratus accounted for 87% of 9,986 specimens of X-disease vector species trapped in orchards during 3 yr and was common from June to November. Thirty-seven percent of 331 P. irroratus leafhoppers, but only 26% of 150 S. acutus leafhoppers transmitted the XDO from diseased celery to celery test plants in greenhouse transmission tests. Twenty-one P. irroratus leafhoppers tested individually transmitted the XDO on 24% of the days (counting from the day of their first transmission) they fed on celery test plants. Four of 15 Orientus ishidae (Mat.) and eight of 44 Scaphoideus, tentatively identified as S. carinatus and as S. diutius or S. melanotus transmitted the XDO to celery. These new vector species were not abundant in cultivated orchards. Paraphlepsius irroratus is considered the most important X-disease vector in Michigan because of its abundance and high transmission efficiency.