The most important tobacco producing areas in Greece were surveyed for virus presence, from 1997 to 2000. Tobacco seedlings or plants showing virus-like symptoms were randomly collected from seedbeds or fields, respectively, and tested by ELISA, and/or mechanical inoculation onto indicator plants. Potato virus Y (PVY), Cucumber mosaic virus (CMV) and Tobacco mosaic virus (TMV) were detected in all sampling areas, with TMV mainly found in oriental varieties. Tomato spotted wilt virus (TSWV) consisted a serious endemic virus in Northern Greece (Thrace, Central and Eastern Macedonia), whereas Alfalfa mosaic virus (AMV) was mainly found in regions, where alfalfa was cultivated in the vicinity of tobacco crops. Eggplant mottled dwarf virus (EMDV) was detected in several areas but always in very low incidence (<0.01%). Surveys were also conducted to assess the potential reservoir hosts of PVY, CMV and AMV among weeds collected from highly infected tobacco fields from 1998 to 2000. Among 3450 samples tested for PVY, plants from 17 species in 10 families were found infected. For CMV, 2891 weed samples were tested and 19 species in 12 families were positive. Assays for AMV infection were made on 961 samples and 12 species in 9 families were identified as hosts of this virus.

A survey was conducted in the Macedonia region of Greece to determine the reservoir hosts of Tomato spotted wilt virus (TSWV) in three tobacco fields and in a greenhouse complex in which lettuce and the ornamentals chrysanthemum, gerbera, aster, and anemone were grown. Assays for TSWV infection were made by enzyme-linked immunosorbent assay on 6,172 plant samples, 3,909 from tobacco fields and 2,263 from the greenhouse complex, comprising plants of 208 species in 137 genera of 42 families. Plants of 86 species out of 63 genera of 27 families were infected of which 39 species are newly reported hosts of TSWV. An infection index was developed to evaluate the relative potential of each weed species as a virus source in both systems. Seventeen species in the tobacco fields and nine in the greenhouses had an infection index higher than one. Most species with infected plants were found in the Compositae family. Plants of some species occurring both in tobacco fields and in greenhouses were infected at only one of these sites. Frankliniella occidentalis was the common thrips species on weeds and crops in the greenhouses, while Thrips tabaci was the only vector on tobacco plants and weeds in the tobacco fields. This observation strongly suggests that the occurrence of species with infected plants and their number have to be attributed to the vector species prevailing in the greenhouse complex or tobacco fields, supporting the conclusion that TSWV is spread in two different epidemiological processes in Greece.

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A contribution to the study of three taxa of the genus Lupinus from North Greece With 2 Figures and 2 Tables Summary ZusammenfassungThe relationships among three taxa of genus Lupinus (L micranthus, L. albus subsp. graecus and L. angustifolius) from Northern Greece were studied. Data of morphometric parameters of fruits and seeds and peroxidase patterns of shoots suggest that: 1. The three studied taxa are separated and distinct. 2. L. micranthus is closer to L angusrifoliirs than to L. albus subsp. graecus. 3. L albus subsp. graecus seems to possess a central position and to be equidistant from L micranthus and L. angustifolius.