© Benaki Phytopathological Institute
Hellenic Plant Protection Journal - Special Issue
12
lation analyses in future studies. The mating
type was unrelated to VCG classification and
probably does not control heterokaryon in-
compatibility in
V. dahliae
.
Interspecific variability and virulence of
Monilinia
spp. isolates in stone
fruits
A. P
APAVASILIOU
, M. V
OLAKAKI
, S. T
ESTEBASIS
and G.S. K
ARAOGLANIDIS
Aristotle University of Thessaloniki, Faculty of Agriculture, Plant Pathology
Laboratory, GR-541 24 Thessaloniki, Greece
Brown rot is the one of the most important
diseases of stone fruits (
Prunus spp
.) world-
wide. The causal pathogens of brown rot
include mainly four species of
Monilinia
:
M. fructigena
,
Μ. fructicola
,
Μ. laxa
and
M.
polystroma
. Until recently
M. fructigena
and
M. laxa
were thought to be the main agents
of brown rot in Europe. However, in recent
years,
M. fructicola
, a quarantine pathogen
in the European Union, has been reported
in many countries of Europe although its
presence had not been confirmed in Greece.
The first objective of this study was to de-
tect the causal pathogens of brown rot in
4 stone fruits crops (peach, cherry, apricot
and plum) in Greece. For this purpose, dur-
ing 2011 and 2012, 1434
Monilinia
spp. iso-
lates were collected from two different geo-
graphical regions: Central Macedonia and
Thessaly. The sampling was conducted dur-
ing 2 phenological stages: blooming and
fruit ripening. All isolates were identified at
a species level, by morphological character-
ization and molecular identification based
on the size of the intron of the
cytochrome
b
gene of
Monilinia
spp. Two species were
detected,
M. laxa
and
M. fructicola,
with fre-
quencies of 59 and 41%, respectively. Spe-
cifically,
M. fructicola
was more common on
fruits (89%) and
M. laxa
was found in equal
frequency in flowers (49.5%) and in fruits
(50.5%). The second objective of this study
was to compare the aggressiveness of the
two species and among isolates of the same
species that were collected from the two dif-
ferent stages of infection; flowering and rip-
ening of fruits. Generally, the pathogenicity
of
M. fructicola
was found to be significantly
higher than that of
Μ. laxa
on the wounded
fruits of cherry and plum, with no significant
difference detected on the wounded fruits
of peach and apricot. Moreover, no signifi-
cant variation in levels of aggressiveness
among isolates from the two different stag-
es of infection was detected. This represents
the first report of
M. fructicola
in Greece. The
wide dispersal of this pathogen and its high
prevalence necessitates further research on
the genetic variability of the fungus, its sen-
sitivity to fungicides, and on the epidemiol-
ogy of the disease in Greece.
Characterization of
Rhizoctonia solani
from potato in Cyprus
L. K
ANETIS
, D. T
SIMOURIS
, D. T
SALTAS
and Ν. Ι
OANNOU
Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus
University of Technology, 3603 Limassol, Cyprus
Eighty isolates of
Rhizoctonia
solani
were
collected from sclerotia formed on the sur-
face of potato tubers during 2011. Isolates
were assigned to the anastomosis group
(AG) using molecular primers (ITS-1 and ITS-
4) from the ribosomal DNA. Phylogenetic
analysis of the obtained PCR products re-
vealed that most of the isolates belonged
to AG-3 (92,8%), while the rest belonged to
the subgroups AG-4-HG-I (2,8%) and AG-4-
HG-II (4,4%), respectively. Optimum growth
rates for the AG-4-HG-I and AG-4-HG-II iso-
lates were at 30°C, while for the AG-3 iso-
lates was at 20°C. Sensitivity of the select-
