© Benaki Phytopathological Institute
Abstracts - 16th Hellenic Phytopathological Congress
7
I
NVITED
L
ECTURES
Phytophthora ramorum
: an emerging pathogen of forest and ornamental
plants in Europe and North America
P. T
SOPELAS
Hellenic Agricultural Organization “Demeter”, Institute of Mediterranean Forest
Ecosystems, Terma Alkmanos, GR-115 28 Athens, Greece
Phytophthoraramorum
is anemergingpatho-
gen with a destructive impact on forest eco-
systems of North America and Europe. It was
described as a new species in 2001, although
has been known since 1993 to infect rhodo-
dendron and viburnum plants in nurseries of
the Netherlands and Germany.
P. ramorum
is considered to be an exotic pathogen, in-
troduced separately into Europe and North
America from an unknown region, speculat-
ed to be Asia. Up to the present, three clon-
al lineages NA1, NA2 and EU1, have been dis-
tinguished by the use of molecular markers
in North America, while in Europe only the
latter (EU1) has been detected. The patho-
gen has a large host range (more than 140
plant species) and the host-list continues to
expand, and includes a significant number
of forest trees and shrubs as well as many or-
namental plants. Certain hosts have shown a
high susceptibility to
P. ramorum
, with lethal
stem and branch infections (formation of
bleeding cankers). In California and Oregon,
the disease, known as “sudden oak death”
(SOD), is lethal to certain oak species (
Quer-
cus
spp.) and tanoak (
Notholithocarpus densi-
florus
), having a devastating impact on forest
ecosystems. Recently (in 2009) the pathogen
was found to cause significant mortality in
Japanese larch plantations in southern Eng-
land. The disease can be also lethal to rho-
dodendron and viburnum plants in nurs-
eries and parks. However, in the majority
of hosts
P. ramorum
causes less serious dis-
eases, infecting mostly the leaves and the
young shoots. In some cases infections are
not conspicuous; the plants are considered
healthy and are transferred by trade, result-
ing in disease spread to new areas.
P. ramo-
rum
is a quarantine organism in Europe,
North America and other areas of the world.
Since 2002 EU regulations have been im-
posed in order to prevent further spread of
P. ramorum
among ornamental plants in the
member countries. Surveys in the EU have
detected the pathogen in 20 of the 27 mem-
ber countries. In Greece,
P. ramorum
was ini-
tially detected in the Phthiotida prefecture
in 2010, on rhododendron plants imported
from Belgium. During 2011-2012 the patho-
gen was found in three more areas of Greece
(Athens, Pelion and Drama), infecting nurs-
ery plants of viburnum and camellia pro-
duced in the country, as well as rhododen-
dron plants imported from Belgium. The hot
and dry climatic conditions in many areas of
Greece do not favour the spread of
P. ramo-
rum
; however, there are many suitable habi-
tats for the establishment of the pathogen,
including natural oak and beech forests in
the highlands as well as maquis scrublands
with evergreen oaks and other hosts of
P.
ramorum
. There is also the possibility of in-
fection of cultivated plants.
Pomegranate diseases. Remarks on Greek and global problems
E.C. T
JAMOS
AND
P.P. A
NTONIOU
Laboratory of Phytopathology, Agricultural University of Athens, 75 Iera Odos Str.,
GR-118 55 Athens, Greece
Pomegranatecultivationhasrapidlyexpand-
ed in recent years in Greece and worldwide.
This presentation refers to findings concern-
ing diseases of pomegranate in Greece ob-
