Page 10 - Volume 1, Issue 1, January 2008

K. Elena et al. 8
mountain of Pelion for its young shoots
which are used for decoration during the
Christmas days (Rumbos, 2006b).
1.1. Concluding remarks
A total of 47 new plant pathogenic fun-
gi have been reported, most of which cause
damaging plant diseases in Greece and only
few seem to have a negligible effect. The new
pathogens were found on a variety of host
plants, annual or perennial, cultivated or for-
est species, vegetables or ornamentals etc.
Based on available information up to
now, the following are among the most
alarming cases:
The introduction of • Ceratocystis platani
to Greece is a threat for the native popu-
lation of Platanus orientalis. It is a recent
introduction and infestation is still in a
restricted area. An aggressive sanitation
program is urgently required to prevent
spread of the pathogen to other areas.
Young-grapevine decline and esca have •
already become serious problems for
Greek viticulture, causing difficulties in re-
planting programs and yield reductions in
established vineyards. Production and use
of certified healthy propagation material
is the basis to manage these problems.
Of • the new vascular wilts caused by
Fusarium oxysporum, the most impor-
tant are the root-stem rot and wilt of cu-
cumber with devastating losses in green-
house cucumber crops and Fusariumwilt
of sweet basil that is now a serious prob-
lem for the commercial crops in Greece.
Alternaria brown spot onMinneolaman- •
darins is a severe problenm in North-
western Greece.
Phytophthora boehmeriae • became a severe
problem in irrigated cotton crops. Crops
with drip irrigation are usually not affected.
2. Plant pathogenic bacteria
Five new records of plant pathogenic pro-
caryotes were reported in Greece since
1990, which were all bacteria. All patho-
gens were found on horticultural cultivat-
ed plants, such as watermelon, celery, leek,
lettuce and artichoke. The bacteria be-
longed to the genera Pantoea, Pseudomo-
nas and Xanthomonas. The methods used
to detect and identify the pathogens in-
cluded cultural, physiological, biochem-
ical, pathogenicity, serological, protein
electrophoresis and molecular tests.
The new plant pathogenic bacteria are
discussed in the text below and summa-
rized in Table 2.
Pantoea ananas  (Serrano) Kergaert,
Verdonk & Kersters [syn. Erwinia ananas
Serano; Pantoea ananatis (Serrano)
Kergaert, Verdonk & Kersters]
The pathogen was reported for the
first time in Greece, in 1992, to infect wa-
termelon (Citrullus lanatus (Thunb.) Mansf.)
fruits in the area of Perama, Rethymnon
prefecture, Crete (Goumas and Hatzaki
1998). Later the pathogen was found sev-
eral times in the same area and in the area
of Messara, Heraklion prefecture, Crete.
The symptoms of the disease which
appeared in the fruit only and not on any
other part of the plants, were similar to
those of the disease known as “watermel-
on rind necrosis”. No symptoms were seen
externally on the fruits during the harvest
period. The symptoms however were re-
stricted to the rind of the fruits. Cut fruits
showed numerous water soaked, yellow-
ish, brown necrotic spots, which formed
necrotic corky areas in the rind. In severe-
ly infected fruits the brown necrotic corky
areas were extended in the rind, but not
in the flesh of the fruit. As a result of the
infection the disease, easily visible in cut
fruits, severely reduced the market value
of the harvest.
The pathogen was detected in plants
by direct isolation and identification using
morphological, physiological, biochemi-
cal and pathogenicity tests (Goumas and