Bidens pilosa

Scientific nameBidens pilosa
English: black jack, beggar’s tick, broom stick, cobbler’s pegs, Spanish needle
Indonesia: ajeran
Lao PDR: pak kwan cham
Myanmar: moat-so-ma-hlan, ta-se-urt
Philippines: borburtak, enwad, kaperek, nguwad, puriket, pisau-pisau, tubak-tubak
Thailand: puen nok sai
Viet Nam: xuyen chi
Annual or evergreen erect herb (up to 1 m tall), hairless stems, fourangled, purplish green in colour, simple or branched.
Leaves: Green, compound with 3–5 leaflets each; leaflets variable but usually egg-shaped with a broader and rounded base tapering towards the end to spear-shaped [3–7 (–10) cm long and 1–2 (–5) cm wide], margins with forward-pointing sharp projections or teeth, terminal leaflet always larger than lateral (side) ones.
Flowers: White petals, centre yellow (7–8 mm wide), usually borne singly on stalks (1 cm long).
Fruits: Achenes (small, dry, one-seeded fruits that don’t open at maturity), black, slender (1.5 mm long), ribbed, 2–4 barbed bristles or awns at terminal end.
Argentina, Belize, Bolivia, Brazil, Chile, Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Peru, Suriname, Uruguay, Venezuela and the Caribbean.
Accidentally as a contaminant.
Roadsides, railway lines, disturbed land, wastelands, fallow land, crops, plantations, managed pasture, gardens, drainage ditches, forest edges/ gaps, woodlands, riversides, lowlands, floodplains and gullies.
Under favourable conditions a single plant can produce 3,000–6,000 seeds per year, with 3–4 generations annually. This, together with its allelopathic properties, allows it to form dense stands rapidly, displacing
native vegetation. In Southeast Asia, this weed is problematic for those growing cabbage, pineapple, guava and plantation crops (Waterhouse, 1993). Densities of eight blackjack plants per square metre, in soybean
fields in Argentina, reduced yields by 43% (Arce et al., 1995). Dry bean harvests in Uganda and Peru were reduced by 48% and 18–48%, respectively, as a result of the presence of B. pilosa. B. pilosa is also a
host and vector to harmful parasites such as root knot nematodes and tomato spotted wilt virus (Mvere, 2004; DPI, 2008).
Witt, Arne. 2017. Guide to the Naturalized and Invasive Plants of Southeast Asia. CAB International. Retrieved from on 8 October 2018
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Last updated on 02/13/2019 20:07