Senecio brasiliensis in the EPPO region: addition to the EPPO Alert List
Senecio brasiliensis (Asteraceae) was recorded in 2021 for the first time in the EPPO region. A naturalised population was found in the Matosinhos port area in Portugal. It has previously been recorded as a causal species in Great Britain. Dana et al. (2021) assess S. brasiliensis as having a high potential of becoming an invasive alien plant species in Europe, due to its biology and that climatic conditions are suitable for the species establishment. The EPPO Panel on Invasive Alien Plants are seeking further information on any additional occurrences of S. brasiliensis the EPPO region.
Geographical distribution
EPPO region: Portugal.
South America: Argentina, Bolivia, Brazil, Paraguay, Uruguay.
Morphology
Erect glabrous herbaceous perennial, 100–200 cm tall, branched and densely leafy throughout. Leaves 6–12 cm long, alternate, sessile, deeply pinnatisect with 2–4 pairs of linear segments 25–50 mm long and +/– 2 mm wide. Inflorescence a terminal multi-flowered corymb; heads radiate, campanulate, 3.5–4 mm diameter., glabrous. Ray florets female, +/– 12 in number; 4–5 mm long, bright yellow. Cypselae densely pubescent, 1.2 mm long, brownish; pappus white, 5 mm long.
Biology and Ecology
Senecio brasiliensis is a perennial shrub which produces a large number of seeds which are wind dispersed. Other species of Senecio are known to have large and persisting seed banks.
Habitats
In its native range, S. brasiliensis is recorded as a serious weed in agriculture. In Portugal, 10–20 individuals were recorded in several habitat types, specifically hygrophilous woodlands, in the fringe of mixed plantations and on disturbed ground dominated by small shrubs, perennial grasses and forbs.
Pathways for movement
It is likely that S. brasiliensis has entered the EPPO region as a contaminant of seed, grain or imported wood material. The Matosinhos port in Portugal receives shipments of logs of eucalyptus imported from Brazil and Uruguay.
Impacts
Senecio brasiliensis can form thick stands which can have the potential to outcompete native plant species. It is reported to be allelopathic and can inhibit seed germination. In South America, it is reported to be one of the main species that can cause natural intoxication of livestock, and it also has negative impacts in agriculture. It can contaminate hay reducing its value. S. brasiliensis has the potential to degrade pastureland in the EPPO region.
Control
Controlling large populations of Senecio species can be difficult due to the persistent seed bank and wind dispersed seeds. Physical control measures can be applied but to be successful, all parts of the plant must be removed.
Sources
Dana ED, Verloove F, Alves P, Heiden G (2021) Senecio brasiliensis (Spreng.) Less. (Asteraceae), another potentially invasive alien species in Europe. BioInvasions Records 10(3), 521–536. https://doi.org/10.3391/bir.2021.10.3.02