Solanum sisymbriifolium
(sticky nightshade)

Preferred Common Name

• sticky nightshade

Other Scientific Names

• Solanum balbisii Dunal
• Solanum bipinnatifidum Larrañaga
• Solanum branciifolium J.Jacq.
• Solanum decurrens Balb.
• Solanum edule Vell.
• Solanum formosum Weinm.
• Solanum inflatum Hornem.
• Solanum mauritianum Willd. ex Roth
• Solanum opuliflorum Port. ex Dunal
• Solanum pilosum Raf.
• Solanum rogersii S.Moore
• Solanum sabeanum Buckley
• Solanum subviscidum Schrank
• Solanum thouinii C.C.Gmel.
• Solanum viscidum Schweigg.
• Solanum xanthacanthum Willd. ex Walp.

International Common Names

• English: dense-thorn bitter apple; manacader; red buffalo-burr; viscid nightshade; wild tomato
• Spanish: alco; cardo; comida de vibora; espina colorada; espino colorado; guidilla de campo; mullaca; ocote mullaca; putui; revienta caballo; tomatillo de campo; tomatillo espinudo; tutia
• Chinese: suan jie qie
• Portuguese: arrebenta-cavalo; joa das queimadas; joa de roca; joão bravo; mata-cavalo; puca-puca

Local Common Names

• Bolivia: puka puka; tomatillo; wilawila
• Germany: Klebriger Nachtschatten
• Lithuania: pilkalapis baklazanas
• South Africa: dense-thorned bitter apple; doringtamatie; tamatiedissel; wildetamatie
• Sweden: blek taggborre

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Solanales
•                         Family: Solanaceae
•                             Genus: Solanum
•                                 Species: Solanum sisymbriifolium

The Solanaceae family comprises 102 genera and 2480 species distributed worldwide, but overwhelmingly across tropical America (Stevens, 2020). Solanum with about 1400 species is the largest genus within the Solanaceae. Molecular and phylogenetic analyses have demonstrated that the formerly separate genera Lycopersicon, Cyphomandra, Normania and Triguera should be all nested within Solanum, thus, all species of these four genera have been transferred to Solanum. Molecular phylogenetic analyses also found that all Solanum species form a strongly supported monophyletic group characterized by a chromosome number based on x = 12 (Olmstead and Palmer, 1992; Olmstead and Sweere, 1994; Olmstead et al., 1999; Bohs, 2005; PBI Solanum Project, 2020).

The following description is adapted from Flora of China Editorial Committee (2020) and PBI Solanum Project (2020):

Herbs to small shrubs, annual or perennial, copiously armed, pubescent with glandular, many-celled, simple and stellate hairs. Stems erect, with yellow or orange-yellow, subulate prickles 2-10 × 1.5 mm. Leaves simple or sometimes pinnate; petiole 1.5-4 cm; leaf blade oblong or ovate, 4.5-10(-14) × 2.5-5(-8) cm, stellate pubescent, sometimes shaggy, often armed along main veins on both surfaces, pinnately lobed or parted; lobes pinnately lobed or dentate, apex acute. Inflorescences axillary or extra-axillary scorpioid racemes; peduncle branched or not. Pedicel 5-10 mm. Calyx cup-shaped, ca. 1 cm; lobes ovate-lanceolate, ca. 5 × 2 mm, pubescent and prickly as on stems. Corolla purplish or white, stellate, 1.6-3.5 cm; lobes ovate, 10 × 4-8 mm, sparsely hairy. Filaments ca. 1 mm, glabrous; anthers lanceolate, ca. 9 mm. Ovary puberulent. Style 1-1.2 cm. Fruiting pedicel 1-1.5 cm, stout. Fruiting calyx enlarged, longer than fruit, densely prickly and enveloping most berry, ultimately flaring wide and exposing it. Berry bright red, subglobose, 1-2 cm in diameter. Seeds reniform, ca. 2.5 × 2 mm.

In Belgium, S. sisymbriifolium was first recorded in 1880 and currently, it is listed as a rare and ephemeral alien usually found on disturbed sites and road verges (Verloove, 2006).

In South Africa, S. sisymbriifolium was first recorded in 1908. It is thought that this species was introduced unintentionally with imported horse fodder. It has become a noxious weed with the potential to smother native vegetation. Currently, it is declared a Category 1 alien invader plant and it may not be planted, propagated, imported, or sold in the country (Hill, 1994; Byrne et al., 2002; Henderson, 2011).

Soil reaction

• acid
• alkaline
• neutral

Soil texture

• heavy
• light
• medium

Natural Dispersal

Solanum sisymbriifolium spreads by seeds and vegetatively by rhizomes. Fruits are consumed and dispersed by animals (e.g. birds and mammals).

Accidental Introduction

Seeds may be dispersed as a contaminant in fodder, mud and agricultural products (Byrne et al., 2002; ISSG, 2020; PBI Solanum Project, 2020). It is thought that S. sisymbriifolium was introduced unintentionally to South Africa with imported horse fodder (Byrne et al., 2002).

Solanum sisymbriifolium behaves as a weed within and outside its native distribution range. It can be a serious weed of pastures and ruderal areas where it grows forming dense spiny thickets that smother native vegetation. It reduces biodiversity in natural forests because it dominates large areas in the understory affecting the germination and establishment of native species. Currently, it is listed as a noxious invasive weed in Australia, South Africa, USA, Cuba, Hungary, Italy, Spain, China and Japan (Mito and Uesugi, 2004; DiTomaso and Healy, 2007; Weber et al., 2008; Campos and Herrera, 2009; Celesti-Grapow et al., 2009; Henderson, 2011; Oviedo Prieto and González-Oliva, 2015; Randall, 2017; Flora of China Editorial Committee, 2020; ISSG, 2020; USDA-NRCS, 2020).

The seeds are poisonous to humans (PBI Solanum Project, 2020).

• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Highly adaptable to different environments
• Is a habitat generalist
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Pioneering in disturbed areas
• Tolerant of shade
• Highly mobile locally
• Benefits from human association (i.e. it is a human commensal)
• Long lived
• Fast growing
• Has high reproductive potential
• Gregarious
• Reproduces asexually

• Ecosystem change/ habitat alteration
• Modification of successional patterns
• Monoculture formation
• Reduced amenity values
• Reduced native biodiversity
• Threat to/ loss of native species

• Competition - monopolizing resources
• Competition - smothering
• Poisoning
• Rapid growth
• Rooting
• Produces spines, thorns or burrs

• Highly likely to be transported internationally accidentally
• Highly likely to be transported internationally deliberately
• Difficult to identify/detect as a commodity contaminant
• Difficult/costly to control

Economic Value

Solanum sisymbriifolium is used as a trap crop for potato cyst nematodes (PCN) such as Globodera rostochiensis and G. pallida that cause massive damage to potato crops in Europe and other countries (Timmermans et al., 2007a, b). The plants induce eggs of PCN to hatch but the standing crop is destroyed before the nematode is able to complete its life cycle. Using S. sisymbriifolium in potato fields helps prevent the potato crop from being infested with PCN and has been shown to reduce populations of PCN by 50-80% (Timmermans et al., 2007a, b; Dandurand and Knudsen, 2016; ISSG, 2020).

The fruits of S. sisymbriifolium are also used as a source of solasodine, a glycoalkaloid used in the synthesis of corticosteroids and sex hormones and a large component of oral contraceptives (Hill and Hulley, 1995).

Social Benefit

Solanum sisymbriifolium is cultivated as an ornamental and the leaves are used in traditional medicine. The berry is edible and consumed by humans in South America, however, the seeds are poisonous (ISSG, 2020; PBI Solanum Project, 2020).