Page 20 - Volume 1, Issue 2, July 2008

Anagnou-Veroniki et al. 72
impeding movement of workers and ma-
chinery. The plant was identified as Ipo-
moea hederacea (L.) Jacquin and was a
new species for the Greek flora (Giannop-
olitis & Papachristos, 1997). A survey con-
ducted in the area during the summer of
2003 revealed that I. hederacea had al-
ready evolved into a serious weed for all
spring crops throughout the valley of the
Louros river. It had also spread well be-
yond the place of its first appearance be-
ing present at high densities in maize
fields throughout another valley (Acher-
on river) of the Preveza prefecture as well
as to many fields in the area of Philipiada
in the neighboring Arta prefecture (Gian-
nopolitis et al., 2004). There was unverified
information that the weed had also spread
to areas near Agrinion in the neighboring
Aitoloakarnania prefecture. I. hederacea is
an annual plant species reproducing by
seed but it also has the potential to root
and regenerate easily from stem cuttings
(Kati & Giannopolitis, 2006). It seems to be
favoured at the above river valley condi-
tions where it emerges from mid-spring
to late summer, grows vigorously, produc-
es many seeds and generally attains all
the characteristics of a very competitive,
extremely troublesome and difficult to
control weed. At present, its distribution
seems to be confined to the western part
of the country.
In 2002, maize growers from Kavala
(Northern Greece), who complained about
having problems with a difficult to con-
trol weed, were asked to send a specimen
for identification. The plant was identified
as Sicyos angulatus L. and its presence
in Greece was reported for the first time
(Giannopolitis, 2003b). Specimens of the
same species were also sent from the area
of Orestiada (Thrace), later in the same
year. It seems that S. angulatus has recently
come to Greece and has been present only
in the northern part of the country, not yet
spread to the south. It is an annual weed
reproducing by seed which becomes par-
ticularly troublesome in irrigated summer
crops by growing vigorously and climb-
ing on the plants. It has a prolonged emer-
gence period, from mid-spring to mid-
summer, and is difficult to control without
the use of residual herbicides. In the area
of Kavala, where the weed was first no-
ticed, soils are organic and effectiveness of
residual herbicides is drastically reduced.
In summer 2003, during a weed survey
in onion crops of the Kopaida area (Central
Greece), a new grass species competing
with the onion plants was observed in a
field near Orchomenos (Viotia prefecture).
The plant was identified to be Panicumdi-
chotomiflorum Michaux, a species new
for the Greek flora (Giannopolitis, 2003a).
The next summer, a survey for the detailed
assessment of the presence of this species
in the wider Viotia area was conducted (Gi-
Table 4. New weed species records in Greece, 1990-2007
Weed species Family Distribution: Areas (crops) Reference
Echinochloa colona Gramineae Locally, minor weed Giannitsaros, 1990
Eleusine indica Gramineae Throughout (lucerne, turf) Giannitsaros, 1990
Ipomoea hederacea Convolvulaceae Western Greece (maize,
cotton, lucerne)
Giannopolitis & Papach-
ristos, 1997
Panicum dichotomiflorum Gramineae Kopaida (maize, cotton, turf) Giannopolitis, 2003a
Paspalum dilatatum Gramineae Throughout (lucerne, turf) Giannitsaros, 1990
Paspalum distichum Gramineae Throughout (lucerne, turf) Giannitsaros, 1990
Sicyos angulatus Cucurbitaceae Kavala, Orestiada (maize) Giannopolitis, 2003b