© Benaki Phytopathological Institute
Hellenic Plant Protection Journal
8:
27-32, 2015
DOI 10.1515/hppj-2015-0005
Laboratory of Weed Science, Benaki Phytopathologi-
cal Institute, 8 St. Delta Str., GR-145 61 Kifissia, Attica,
Greece
E-mail:
SHORT COMMUNICATION
Wild poinsettia (
Euphorbia heterophylla
): an emerging weed in
cotton and processing tomato in Greece
D. Chachalis
Summary
Euphorbia heterophylla
(wild poinsettia) is reported as an emerging weed in cotton and
processing tomato in Kopaida plain, region of Viotia, in central Greece. This is the first record of
E. het-
erophylla
in tomato crop in Greece. In a field experiment, mature plants grown under weed-free con-
ditions produced on average 19 heads, 64 capsules, and 192 seeds per individual plant. Mature seeds
exhibited no dormancy and the maximum germination (82 to 90%) occurred at temperatures from 25
to 35
o
C, with a drastic decline (<38%) at 15 and 40
o
C. Light had no significant effect on seed germina-
tion in the whole range of temperatures tested. Fully mature plants were taller than cotton, exerting
strong competition. Having no light dependence for germination, seeds might have the potential to
germinate and emerge from greater soil depths. This short communication summarizes information
for the identification, seed germination and growth of this weed species that would support a prop-
er weed management.
Additional keywords
: germination, growth, invasive, noxious, weeds
Euphorbia heterophylla
(wild poinsettia) is
native to Central and South America (Wilson,
1981). Today it is widely distributed through-
out the tropics, subtropics and the Mediter-
ranean region. Moreover, it is widely spread
as an important weed in at least 28 tropi-
cal countries and it is present in another 37
countries (Wilson, 1981). In countries where
the species is present, research has been di-
rected mainly towards suitable methods for
its control in crops such as peanuts and soy-
beans (Moore
et al.
1990; Willard and Griffin,
1993; Brecke and Tobola, 1996). First occur-
rence of
E. heterophylla
in Greece, was re-
corded in cotton crop in 2008 (Chachalis and
Travlos, 2009). Since then, the species has
become a major weed problem in the area
Anthochori, Kopaida plain, Viotia, infesting
mainly cotton and processing tomato fields.
This is the first record of
E. heterophylla
in to-
mato crop in Greece. This study investigat-
ed the seed germination and growth of this
species contributing with useful results for
the effective management of the weed.
Morphological Description
Euphorbia heterophylla
is a monoecious an-
nual plant, sparsely branched, up to 140
cm tall (Figure 1). Stem is often tinged red
towards the apex; leaves are arranged spi-
rally, crowded at stem apex, simple having
stipules modified into purplish glands (Mo-
sango, 2008). Inflorescence is a compact ax-
illary or terminal cyme consisting of clusters
of flowers (cyanthia), each with basal bracts
similar to the leaves, but paler green, with
involucres containing one female flower
surrounded by many male flowers (Mosan-
go, 2008). Fruit is a deeply 3-lobed capsule;
seeds are ovoid, 2.5 mm in diameter, warty,
blackish brown, and the embryo is located
towards the apex of the seed (Figure 2).
