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Ecology and Epidemiology

Epidemiology of Peach Rosette Mosaic Virus in a Concord Grape Vineyard. D. C. Ramsdell, Associate Professor of Plant Pathology, Department of Botany and Plant Pathology, Michigan State University, East Lansing, MI 48824; R. L. Myers, Technician, Department of Botany and Plant Pathology, Michigan State University, East Lansing, MI 48824. Phytopathology 68:447-450. Accepted for publication 12 September 1977. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-447.

A block of 165 Vitis labrusca ‘Concord’ grapevines was sap indexed to Chenopodium quinoa on an individual vine basis for 4 yr to determine the rate of spread of peach rosette mosaic virus (PRMV). The first indexing in 1974 revealed 15 infected vines. In 1975, 1976, and 1977, there were 14, 3, and 8 newly infected vines, respectively. Spread was slow and mostly to vines adjacent to previously infected vines. The pattern of spread was elliptical. Indexing the roots of 16 weed species associated with diseased vines revealed that curly dock (Rumex crispus), Carolina horsenettle (Solanum carolinense), and common dandelion (Taraxacum officianale) were infected. The virus was found to be seedborne in 5/137 (3.6%) dandelion seedlings assayed from mother plants. Grape seedlings from fruit of infected vines contained PRMV in 4/38 seedlings (9.5%) assayed onto C. quinoa. Pollen apparently did not contain virus. The presumed vector Xiphinema americanum was found to depths of 152.4 cm (5 feet) and 213.4 cm (7 feet) beneath PRMV-infected vines in two vineyards.