Solanum sisymbriifolium in the EPPO region: addition to the EPPO Alert List
Why
Solanum sisymbriifolium is native to South America and has been introduced into the EPPO region for ornamental purposes. In Sardinia (IT), the first observation was made in 1983 (accidental introduction) and the plant has since significantly increased its distribution range in coastal regions.
Geographical distribution
EPPO region: Austria, Belgium, Czech Republic, Denmark, Ireland, Estonia, France, Italy, Latvia, Lithuania, Morocco, Netherlands, Norway, Portugal, Spain, Turkey, Ukraine.
Asia: China (Guangdong, Yunnan), India, Republic of Korea, Taiwan.
Africa: Benin, Kenya, South Africa.
North America: United States (Alabama, Arizona, California, Delaware, Florida, Georgia, Iowa, Louisiana, Massachusetts, Mississippi, New Jersey, New York, North Carolina, Oregon, Pennsylvania, South Carolina, Texas).
South America: Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Paraguay, Peru.
Oceania: Australia (New South Wales, Victoria, Western Australia).
Morphology
Erect annual or short-lived perennial herb 1 to 2 m tall, green, pubescent with glandular and stellate hairs; spines up to 13 mm long, abundant on most parts.
Leaves: ovate-lanceolate; lamina 5-14 cm long, 4-10 cm wide, concolorous, lobed; lower lobes often forming leaflets; petiole up to 4 cm long.
Inflorescence: up to 12-flowered; peduncle up to 45 mm long; rachis up to 15 cm long; pedicels 10-15 mm long, elongated slightly in fruit. Calyx 6-12 mm long, enlarged in fruit; lobes lanceolate, 4-7 mm long. Corolla stellate, 35-50 mm diameter, white or pale blue. Anthers 8-10 mm long.
Fruit: globular berry, 15-20 mm diameter, bright red. Seeds 2-2.5 mm diameter.
Biology and Ecology
Solanum sisymbriifolium mainly spreads by seed. Each plant can produce up to 45 000 seeds each year in tomato-like fruit which can be spread by birds. It can grow in shade and full sunlight and in a variety of soil types.
Habitats
Solanum sisymbriifolium can occur in agricultural areas including irrigated crops and pastures. The species grows in ruderal and disturbed habitats and is found in urban and semi-urban areas. The species also grows in coastal areas. In the USA, it is found growing along the side of roads and in Australia, it is found growing in woodland dominated by eucalypts.
Pathways for movement
Solanum sisymbriifolium is used as a trap crop for potato cyst nematodes (PCN), such as Globodera rostochiensis and G. pallida because it stimulates the hatching of juvenile PCN from their cysts by root diffusates but it is resistant to infestation by the juveniles once they hatch, preventing reproduction of the nematodes. The species is also available in the horticultural trade for its aesthetic value and edible fruit. S. sisymbriifolium can also be spread as a contaminant of hay.
Impacts
In Sardinia (IT) S. sisymbriifolium is considered a threat for irrigated crops. It also has the potential to compete with native plant species, thereby reducing rangeland biodiversity and pastoral value. However, there are no studies that have quantified the impact of the species on agriculture or the environment. S. sisymbriifolium has sharp spines covering the stems which can make them dangerous to livestock and humans.
Control
Mechanical control is difficult as the species can regrow after cutting. The leaf-feeding tortoise beetle Gratiana spadicea (Coleoptera: Chrysomelidae) has been released against S. sisymbriifolium in South Africa.
Sources
Dandrand LM, Knudsen GR (2016) Effect of the trap crop Solanum sisymbriifolium and two biocontrol fungi on reproduction of the potato cyst nematode, Globodera pallida, Annals of Applied Biology 169 180-189.
EPPO (2008) Solanum sisymbriifolium in Sardinia (IT) EPPO Reporting Service no.11-2008 https://gd.eppo.int/reporting/article-854
King AM, Brudvig R, Byrne MJ (2011) Biological control of dense-thorned bitter apple, Solanum sisymbriifolium Lam. (Solanaceae), in South Africa. African Entomology 19, 427-433.
Lanza B, Camarda I, Natali A (1995) Solanum sisymbrifolium Lamarck, an alien new to Sardinia. Bollettino Museo Regionale di Scienze Naturali di Torino 13, 289-295.
Usai M, Foddai M, Brunu A, Azara E, Camarda I (2008) [Solanum sisymbrifolium Lamarck exotic casual weed of Sardinia: spread and phytochemical aspects]. Natural Diciembre 2008, 22-26 (in Italian).
USDA (2013) Weed risk assessment for Solanum sisymbriifolium Lam. (Solanaceae) – sticky nightshade. Available at: https://www.aphis.usda.gov/plant_health/plant_pest_info/weeds/downloads/wra/Solanum_sisymbriifolium_WRA.pdf