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Disease Note. Dodder Transmission of Tomato Ringspot Virus. R. A. Welliver, Pennsylvania Department of Agriculture, Harrisburg 17110. J. M. Halbrendt, The Pennsylvania State University Fruit Research Laboratory Biglerville 17307. Plant Dis. 76:642. Accepted for publication 15 January 1992. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-0642C. Tomato ringspot virus (TmRSV), causal agent of Prunus stem
pitting, is transmitted by dagger nematodes (Xiphinema spp.) to fruit
trees in the northeastern United States. Because weed reservoirs of
TmRSV have been identified as important factors in virus spread
(1), Cuscuta gronovii Willd. ex Roem. & Schult., a common dodder
species in Pennsylvania, was tested for its ability to vector TmRSV
between weed hosts. C. gronovii seed was collected from flowering
strands established on Chenopodium album L. in a Pennsylvania peach
orchard. The dodder seed was cogerminated with Chenopodium
quinoa Willd. in the greenhouse. Dodder seedlings tested negative for TmRSV and tobacco ringspot virus by enzyme-linked immunosorbent
assay (ELISA). The dodder was first trained to TmRSV infected
Chenopodium quinoa and, when established, was trained back
to healthy Chenopodium quinoa or Cucumis sativus L. Healthy plants
were shaded for 1 wk after contact with dodder. TmRSV infection
was confirmed by systemic symptom development and by ELISA in
21 of 26 plants. Our results indicate that dodder could have a role
in local epidemiology of Prunus stem pitting by facilitating TmRSV
transmission among weed species. |