In 2002, severe vein yellowing and partial or complete yellowing of leaves was observed on some shoots of red raspberry (Rubus idaeus) cvs. Golden Bliss and Autumn Bliss. Sap of infected plants of cv. Golden Bliss was inoculated onto Chenopodium quinoa and Nicotiana benthamiana. Faint chlorotic spots were observed on inoculated leaves of C. quinoa approximately 14 days after inoculation but no systemic symptoms appeared. No symptoms were observed on N. benthamiana. Raspberry bushy dwarf virus (RBDV) was detected in the original raspberry plant using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) with polyclonal antiserum (Loewe Biochemica, Sauerlach, Germany). Systemic infections of inoculated C. quinoa and N. benthaminana were confirmed using DAS-ELISA. In 2001 and 2002, unusual virus symptoms were observed on grapevine grafts (Vitis vinifera) of cv. Laški Rizling. Symptoms appeared as curved line patterns and yellowing of the leaves. No nepoviruses were found in symptomatic plants, but RBDV was confirmed using DAS-ELISA. RBDV infection was later confirmed in grapevine cv. Štajerska Belina with similar symptoms. RBDV was transmitted mechanically from grapevine to C. quinoa where it was detected by immunocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR). IC-RT-PCR was used to amplify a part of the coat protein gene of the virus from raspberry and grapevine, and the amplification products were sequenced (1). The obtained sequence shared at least 93% nucleotide sequence identity with other known RBDV sequences, which confirmed the serological results. To our knowledge, this is the first report of the natural occurrence of RBDV in grapevine and also of RBDV infection of red raspberry in Slovenia. Reference: (1) H. I. Kokko et al. Biotechniques 20:842, 1996.

Rupestris stem pitting associated virus (RSPaV), a member of the genus Foveavirus, is associated with the Rupestris stem pitting component of the Rugose wood (RW) disease complex of grapevines. Heretofore, particles of RSPaV have not been visualized. In this work, flexuous rod particles approximately 723 nm in length were detected in the sap of infected grapevines by immunosorbent electron microscopy (ISEM), using a polyclonal antiserum produced to a recombinant coat protein of RSPaV. Particles of RSPaV were detected in tissue culture-, greenhouse-, and field-grown grapevines infected with RSPaV, but not in healthy control plants. Detection of virus particles by ISEM corresponded with detection of RSPaV by Western blot, enzyme-linked immunosorbent assay, and reverse transcription-polymerase chain reaction. Virus particles were decorated with the antibodies specific to RSPaV but not with antibodies to Grapevine virus A or Grapevine virus B, two other viruses believed to be associated with RW. This definitive identification of RSPaV particles will help define the etiology of RW.

In July 2000, concentric necrotic rings and patterns were observed on greenhouse-grown pepper (Capsicum anuum L. ‘Blondi’). Symptoms were present only on lower leaves, not on young leaves or fruits. Typical tospovirus particles using electron microscopy were observed in leaf-dip preparations of symptomatic leaves. Impatiens necrotic spot virus (INSV) was detected in symptomatic but not in asymptomatic tissues using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) with polyclonal antiserum (Loewe Biochemica, Sauerlach, Germany). Nicotiana benthamiana, N. rustica, and Petunia sp. were mechanically inoculated with sap of symptomatic leaves. Local and systemic symptoms were observed only on N. benthamiana. Tomato spotted wilt virus (TSWV) infections were later confirmed in some pepper and tomato plants with distinct systemic symptoms and in greenhouse-grown chrysanthemums, calla lilies, cyclamen and spatiphylum using DAS-ELISA with polyclonal antiserum. Severe systemic symptoms were observed only on some chrysanthemum cultivars, where the infection rate of TSWV was between 80 and 100%. Such TSWV-infected plants were not marketable. Symptomless infections by the same virus were also found. At one location, calla lilies were heavily infected by TSWV, but only local symptoms on leaves were observed. INSV was also confirmed using DAS-ELISA on different chrysanthemum cultivars. Mixed infections of TSWV and INSV were detected using DAS-ELISA on calla lilies with local necrotic rings and patterns on leaves and on Impatiens walerana with systemic necrosis. A limited number of weeds from the vicinity of greenhouses containing symptomatic plants were tested for the presence of TSWV using DAS-ELISA, and only Artemisia vulgaris was infected. Both viruses, TSWV from chrysanthemum and INSV from pepper, were isolated on test plants, and their identity was confirmed using DAS-ELISA. For further verification of TSWV and INSV infection, immunocapture reverse-transcription polymerase chain reaction was performed using general tospovirus primers (1). Amplification products of the expected size were detected and sequenced. Comparison of nucleic acid sequences of amplification products with viral sequence databases confirmed the identities of both viruses. To our knowledge, this is the first report of TSWV and INSV infection in ornamental and vegetable plants in Slovenia. Reference: (1) R. J. Weekes et al. Acta Hortic. 431:159, 1996.

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