Page 11 - Volume 1, Issue 1, January 2008

New plant pathogens in Greece 9
Hatzaki, 1998).
Measures of integrated control (de-
stroy infected plant debris and fruits, crop
rotation with resistant hosts, sprays with
copper compounds [at least after petal
drop]) are recommended to eliminate the
disease incidence.
Pseudomonas syringae  pv. apii
(Jagger) Young, Dye & Wilkie
The pathogen was found in 2003 for
the first time in Greece, to infect cultivat-
ed celery (Apium graveolens L.) plants in
the area of Heraklion prefecture and other
places of Crete (Goumas and Lalla, 2004).
Thesymptomscausedby thepathogen,
were initially small water soaked spots, cir-
cular or angular, usually on old leaves, sur-
rounded by a chlorotic halo. Gradually the
spots became yellow, necrotic and brown.
Under favorable conditions they enlarged,
coalesced and resulted in the necrosis of
whole leaves. The pathogen P. s. pv. apii
was reported to be transmitted with celery
seeds (Little et al., 1997; Goumas and Lal-
la, 2004) and hot water treatment of seeds
was reported (Bant and Storey, 1952), as a
measure against the pathogen.
The pathogen was detected in plants
by direct isolation, and identification, us-
ing morphological, physiological, bio-
chemical and pathogenicity tests.
Since the pathogen affects leaves the
main marketable part of the plant, when
the infection is spread in the culture, there
is a considerable economic loss.
Measures of integrated control (hot wa-
ter treatment of seeds at 50°C for 25 min., de-
struction of infected plants and plant debris,
use of drip instead of overhead irrigation,
sprays with copper componds) are recom-
mended to diminish the disease incidence.
Pseudomonas syringae  pv. porri
Samson, Shafik, Benjama, Gardan
The pathogen was found in 2000 for
the first time inGreece, to infect leek plants
(Allium porrum L.) a vegetable crop of mi-
nor uses cultivated in the area of Megara,
Attiki (Glynos and Alivizatos, 2006).
The symptoms appeared on leaves of
almost all plants, as small, oily, longitudi-
nal or irregular spots without halo. Later
the spots enlarged, coalesced and spread
across the leaf blades. Subsequently the
leaves showed a chlorosis at the tips, wilt-
ed, dehydrated and finally they collapsed.
The spread of the infection to the base of
the leaves caused their shrinkage and ne-
crosis. Severely diseased plants remained
small and unsuitable for the market.
The detection of the pathogen in infect-
ed leek plants was easily performed by direct
isolation, morphological, biochemical, sero-
logical, pathogenicity tests and by analysis
of the whole cell protein profile on PAGE.
Measures of integrated control (de-
stroy infected plants and plant debris,
crop rotation, avoid overhead irrigation,
sprays with copper compounds) of P.s. pv.
porri are recommended.
Xanthomonas campestris  pv. vitians
(Brown) Dye
The pathogen was found for the first
time in Greece in 1992 to cause a serious
disease of lettuce (Lactuca sativa L.) in At-
tica (Alivizatos and Glynos, 1992).
The symptoms produced by X. c. pv. vi-
tians on lettuce leaves were initially small
water-soakedoily, circular or angular trans-
lucent spots (0.5-1 mm in diameter) which
progressively became larger (5-6 mm in
diameter) and darkbrown. The symptoms
were more advanced in old leaves and re-
sulted in a serious economic loss, since
lettuce heads lost their market value.
The detection of the pathogen in infect-
ed plants was easily performed by direct
isolation and identification using morpho-
logical, physiological, biochemical, pathoge-
nicity tests and the profile of cell proteins on
PAGE (Alivizatos and Glynos, 1992). A semise-
lective medium was also reported (Toussaint
et al., 2001) for the isolation of X. c. pv. vitians
from soil and plant debris. Susceptibility of
lettuce to the pathogen varied among culti-