Page 14 - Volume 1, Issue 1, January 2008

K. Elena et al. 12
classified family Closteroviridae). Surveys in
different regions of the country and subse-
quent serological and/or molecular analysis
revealed high incidence of GLRaV-1 and -3
(12-42.4%, 21-47.8%) (Avgelis et al., 1997; Do-
vas et al., 2003a, b; Maliogka et al., 2006b),
important incidence of GLRaV-2 in North-
ern Greece (22%) (Dovas et al., 2003a) and
lower in Southern Greece (9.3%) (Maliog-
ka et al., 2006b), occasionally of GLRaV-5
(8.67-42%) (Dovas et al., 2003b; Maliogka
et al., 2006b) and GLRaV-4 (12.67%) (Mal-
iogka et al., 2006b) and also presence of
GLRaV-6 and GLRaV-7 (Dovas et al., 2003b;
Maliogka et al., 2006b). Furthermore, two
putatively new ampeloviruses that were
recently isolated from Greek grapevine va-
rieties Debina and Prevezaniko respective-
ly were detected in a survey (4-6.66%) (Ma-
liogka et al., 2006b). Most of the Grapevine
leafroll-associated viruses are spread pri-
marily through infected propagating ma-
terial and grafting. However increasing ev-
idence suggests that GLRaV-1 and GLRaV-3
are also transmitted by soft scale insects
and mealybugs (Coccoidea) respectively.
Recently, it was also shown that, under lab
conditions, GLRaV-5 and GLRaV-9 are also
transmitted by mealybugs.
Grapevine rugose 
wood-associated viruses
Rupestris stem pitting appears to be
the most widespread disease of the ru-
gose wood complex of grapevines. Rupes-
tris stem pitting associated virus-1 (RSPaV-1,
genus Foveavirus), a recently character-
ized virus, is closely associated with the
disease and was detected in high inci-
dence (>80%) in grapevines of Northern
Greece (Dovas et al., 2001c).
Other diseases are Kober stem groov-
ing and Grapevine corky bark which are
caused by Grapevine virus A (GVA, genus
Vitivirus) and B (GVB, genus Vitivirus), re-
spectively, are also present in Greece. GVA
is the most widespread with an overall in-
cidence of 29.5% (Avgelis and Rumbos,
2000) whereas in Crete it was detected in
54.8% of mother plants of local wine va-
rieties (Avgelis and Grammatikaki, 2006).
Rugose wood is distributed over distances
by infected propagation material, where-
as spread of GVA and GVB in the vineyards
is mediated by pseudococcid mealybugs.
The poor sanitary status of grapevines es-
pecially those grafted on American root-
stocks has been demonstrated together
with the need of organization of a virus
certification scheme in the country.
Viroids 
Viroids have been only recently iden-
tified by molecular methods first in pome
and then in stone fruits in Greece. Apple
scar skin viroid (ASSVd, genus Apscaviroid ),
Pear blister canker viroid (PBCVd, genus Ap-
scaviroid) and Peach latent mosaic viroid
(PLMVd, genus Avsunviroid ) were report-
ed to infect naturally wild (Pyrus amyg-
daliformis Vil.) and cultivated pear (Pyrus
communis L.) in Greece in 1998 (Kyriako-
poulou and Hadidi, 1998). Among those,
ASSVd on apple (Malus domestica Borkh.)
and PLMVd on peach (Prunus persica (L.)
Batsch) are known to induce the most seri-
ous diseases. ASSVd causes severe scar skin,
dappling or cracking on the surface of ap-
ple fruit and the affected trees of suscepti-
ble cultivars produce unmarketable fruits.
PLMVd is responsible for rapid ageing of the
trees, which produce irregularly shaped,
flattened, colourless fruits with cracked su-
tures. Scar skin disease, originally observed
in a severely damaged commercial pear or-
chard, was later found widespread in culti-
vated and wild pear in Northern Pelopon-
nese. In Greece, wild pear has traditionally
been used as rootstock of pear and apple,
and pear infection has obviously been tak-
ing place by grafting on infected wild pear
rootstock or using infected budwood.
During 2003-2004, ASSVd was in ad-
dition detected in apple (Peloponnese,
Etoloakarnania, Magnesia), PLMVd in apri-
cot (Prunus armeniaca L.) (Peloponnese,