Acalypha australis in the EPPO region: addition to the EPPO Alert List
Why
Acalypha australis (Euphorbiaceae) is recorded in a few EPPO countries. The species has the potential to cause economic impacts in agricultural systems in the EPPO region. The Panel on Invasive Alien Plants have added Acalypha australis to the Alert List with the aim to collect further information on established populations and evidence of impact.
Geographical distribution
EPPO region: Albania, Azerbaijan, Bulgaria, Italy (including Sicily), Russian Federation (Far East*), Türkiye, Ukraine, Uzbekistan
Asia: China* (except Xinjiang), Iraq, Japan*, Korea* (Democratic People’s Republic of), Korea* (Republic of), Laos*, Philippines*, Vietnam*
North America: USA (Iowa, New York)
Oceania: Australia (New South Wales, Queensland, Victoria)
* = Native range
Morphology
Acalypha australis is a short plant growing up to 50 cm. Leaves oblong to lanceolate 3-9 × 1-5 cm. Male inflorescences 1–2 cm long. Female flowers 1 or 2, concealed within each bract approximately 10–15 mm in diameter. The peduncle is approximately 10 mm long. Fruit are approximately 3 mm in diameter. Seeds are subovoid, 1.5-2 mm, smooth.
Biology and Ecology
Acalypha australis is an annual erect species which can produce up to 300 seeds per plant. Plant grows on light (sandy), medium (loamy), and heavy (clay) soils. It can grow in acidic, neutral, and alkaline soils. In Asia, A. australis is considered a medicinal plant that can cure various ailments.
Habitats
In the EPPO region, A. australis is present along road embankments and in waste lands. In the USA (Iowa), A. australis is reported in agricultural areas, in particular maize fields where its occurrence has increased since its initial finding in 2016. There are also reports that it can grow in grasslands, wooded habitats and along riverbanks. A. australis has the potential to invade a variety of habitats in the EPPO region.
Pathways for movement
Acalypha australis can be spread as a seed and grain contaminant. Additionally, A. australis has the potential to spread via agricultural practises including movement of machinery and equipment. Natural spread via seed can promote local spread of the species.
Impacts
Acalypha australis can cause economic losses in a number of crops including cotton, maize, root and tuberous crops, and vegetables. In China, A. australis can grow in maize at densities of 10 to 100 plants m-2.
Control
There is little information on the control of A. australis. There are reports that A. australis is resistant to glyphosate and group 14 herbicides. In some habitats, hand-pulling and mechanical control can be successful in controlling small populations.
Sources
Abdiyeva RT, Litvinskaya SA (2021) New locations and distribution of the alien species Acalipha australis L. (Euforbiaceae) in Azerbaijan. Plant & Fungal Research 4, 19-2
Makhkamov T, Kortz A, Hejda M, Brundu G, Pyšek P (2024) Naturalized alien flora of Uzbekistan: species richness, origin and habitats. Biological Invasions 26, 2819–2830.
Mamchur T, Shynder O, Chorna H, Doiko N, Kabar A, Kalashnik K, Parubok M, Levon A,
Baranovsky B, Karmyzova L, Lyubinska L, Zhuravlova T, Shevera M (2023) The genus Acalypha (Euphorbiaceae) in Ukraine. Journal of Native and Alien Plant Studies 19, 78-94
Saliaj O, Mesiti A, Mullaj A (2024) Acalypha australis (Euphorbiaceae), a new alien species in the urban areas of Tirana (Albania). Flora Mediterranea 34, 5-11.
USDA (2012) Weed Risk Assessment for Acalypha australis L. (Euphorbiaceae) – Asian copperleaf. United States Department of Agriculture, Version 2