Page 36 - Volume 2, Issue 1, January 2009

Hellenic Plant Protection Journal

2:

37-40, 2009

SHORT COMMUNICATION

Galinsoga ciliata

(Raf.) S.F. Blake and

Sida spinosa

L., two new

weed records from Greece

S. Lymperopoulou and C.N. Giannopolitis

Summary

Two weed species are reported for the first time to occur in Greece.

Galinsoga ciliata

(Raf.)

S.F. Blake (Asteraceae) was found at high densities in vegetable crops in the area of Marathon, near Ath-

ens. S

ida spinosa

L. (Malvaceae) was found to be present as few scattered plants in cotton fields in the

valley of Louros, near Preveza (Southwestern Greece) and in the area of Palamas, near Carditsa (Cen-

tral Greece). Both species are considered as invasive alien plants, not previously included in the flora of

mainland Greece (the former) and of Greece (the latter). Distinguishing characteristics of the two spe-

cies are presented.

Additional keywords:

alien plants, Asteraceae,

Galinsoga parviflora

, Greek flora, Malvaceae,

Sida rhombifolia

ada and many European countries (6). It

is regarded as an invasive alien plant spe-

cies already established in most Europe-

an countries, but not known to be present

in Greece yet (2). Although there has been a

report of its presence in the Greek island of

Samos since 1993 (10) and in the Izmir prov-

ince (West Anatolia) of Turkey since 2003 (7),

its presence in mainland Greece is reported

here for the first time.

The only other species of the genus,

G.

parviflora

Cav., which is also an important

weed, morphologically very similar to

G. cil-

iata

, has been reported to occur in Greece

since 1983 (5) and is now thought to have

spread throughout the country. It is very

likely, therefore, that

G. ciliata

has been pres-

ent in Greece for long but remained unrec-

ognized from

G. parviflora.

Both species are annual plants reproduc-

ing by seed. They have upright stems with

many branches and reach a height of 10-80

cm at maturity. They are recognized from

the opposite simple ovate leaves and the

small (<1 cm) flower heads consisting of 4-5

white, 3-toothed ray florets and many yel-

low disk florets (Figure 1). Distinction of the

G. ciliata

plants was mainly based on the fol-

lowing specific characters (11):

Galinsoga ciliata

(Raf.) S.F. Blake [synonym

G.

quadriradiata

auct., non Ruiz et Pav.], Aster-

aceae, was found for the first time in October

2003 in cabbage crops in the area of Mara-

thon, a vegetable producing area near Ath-

ens. Observations during the years 2004-08

indicated that the species is established in

this area primarily in fields grown to vege-

tables, where it occurs at high densities dur-

ing summer and autumn. Occasionally it is

also found in greenhouses grown to veg-

etables or ornamentals and in uncultivat-

ed land. The plant seems to produce many

seeds which germinate soon after their rip-

ening and falling to the soil, as one can find

plants of all stages to be present in a field at

the same time. The system of continuous in-

tensive vegetable growing, which is applied

in the area, with frequent fertilization and ir-

rigation, apparently favors the plant to at-

tain a proliferous growth.

G. ciliata,

a native to South and Central

America, has now become one of the most

common weeds in the United States, Can-

1

Laboratory of Chemical Weed Management, Depart-

ment of Weed Science, Benaki Phytopathological In-

stitute, 8 St. Delta str., GR-145 61 Kifissia (Athens),

Greece.

Corresponding author:

C.Giannopolitis@bpi.gr