Erigeron karvinskianus (Karwinsky`s fleabane)

Erigeron karvinskianus ( Karwinsky’s fleabane)
Perennial herb, frequently creeping and fragile, with small white or pink flowers that look like a small
daisy.
Scientific name: Erigeron karvinskianus DC.
Common names: Karwinsky's fleabane, daisy fleabane, daisy, Latin American fleabane, Mexican daisy,
seasurface daisy
Family: Asteraceae (Compositae)
Status in Portugal: invasive species (listed in the annex I of Decreto-Lei n° 565/99, 21 December)
Risk Assessment score: (in development)
Synonymy: Erigeron mucronatus DC.
Last update: 11/07/2014
How to recognise it
Perennial herb of 15-50 cm, ramified, sub-ligneous on the
base and a fragile look.
Leaves: with an obovate to a cuneate base, with a short
petiole, generally with 3 lobes; upper leaves linear-lanceolate,
entire.
Flowers: arranged in small capitula (with less than 1 cm
diameter) with thin and long peduncles (3-8 cm); marginal
ligulate flowers, hairlike, white or pink on the upper and
purple on the lower surface; yellow disk flowers.
Fruits: cypselas, where some have a brownish pappus of long
hairs.
Flowering: February to September.
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Capitula of white marginal flowers and yellow
disk flowers
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Erigeron karvinskianus (Karwinsky’s fleabane)
Similar species
There are several similar species of “white and yellow daisies”. However, E. karvinskianus has smaller
capitula than most other species. One of the most similar species is Bellis annua L. ((annual daisy), which
is annual with only 5-12 cm, normally leaves that are broader and cypselas without pappus.
Characteristics that aid invasion
It propagates by seed producing many seeds, which are easily dispersed by the wind. It also propagates
vegetatively from rhizomes.
ORIGIN AND DISTRIBUTION
Native distribution area
Mexico and tropical South America.
Distribution in Portugal
Mainland Portugal (Minho, Trás-os-Montes,
Douro Litoral, Beira Alta, Beira Baixa, Beira
Litoral, Estremadura, Ribatejo, Alto Alentejo),
Azores archipelago (all islands), Madeira
archipelago (Madeira island).
Other places where the species is invasive
Europe (Spain), New Zealand, western USA
(California).
Introduction reasons
For ornamental reasons, continuing to be grown in gardens.
Preferential invasion environments
Rupicolous habitat: walls, cracks on rocks and cobblestones; it also grows next to gardened spaces,
frequently disturbed, from where it was planted.
IMPACTS
Species with an invasive behaviour, mainly in the north of the country.
Impacts on ecosystems
It forms continuous mats that smother of native species when competing for space, water and nutrients .
Natura 2000 network habitats more subject to impacts

Calcareous rocky slopes with chasmophytic vegetation (8210);

Siliceous rocky slopes with chasmophitic vegetation (8220).
CONTROL
Controlling an invasive species demands a well-planned management, which includes the determination
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Erigeron karvinskianus (Karwinsky’s fleabane)
of the invaded area, identifying the causes of invasion, assessing the impacts, defining the intervention
priorities, selecting the adequate control methodologies and their application. Afterwards it is
fundamental to monitor the efficiency of the methodologies and recuperation of the intervened area as
to perform, whenever necessary, the follow-up control.
The control methodologies used for Erigeron karvinskianus include:
Physical control
Hand pulling: preferential methodology. It should be done before fruit maturation. In more compacted
substrates, hand pulling should be done in the rainy season as to facilitate the removal of the entire root
system. It should be guaranteed that no roots remain in the soil.
Chemical control
Foliar application of herbicide. Spray with herbicide (active principle: glyphosate) limiting the exposure
as much as possible to the target species.
For additional information, visit the webpage www.invasoras.pt and/or contact us at [email protected].
REFERENCES
Betancort JAR, Guerra AS, Silva L, Carvalho JA (2008) Erigeron karvinskianus R. Br. In: Silva L, Land EO, Luengo JLR (eds) Flora e
fauna terrestre invasora na Macaronésia. Top 100 nos Açores, Madeira e Canárias. Arena, Ponta Delgada, pp. 275-278.
Global Invasive Species Database (2012) Erigeron karvinskianus. Available: http://www.issg.org/database/species/ecology.asp?
si=1278&fr=1&sts=&lang=EN [Retrieved 10/11/2012].
Marchante E, Freitas H, Marchante H (2008) Guia prático para a identificação de plantas invasoras de Portugal Continental.
Imprensa da Universidade de Coimbra, Coimbra, 183pp.
Weedbuster (2012) Erigeron karvinskianus. Available: http://weedbusters.co.nz/weed_info/detail.asp?WeedID=21 [Retrieved
10/11/2012].
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