Crop Protection Online > Pests - Weed biology<br> <sub>Agro-region: Denmark</sub> - Bidens tripartita L.

Crop Protection Online

20.4 2024

Weed biology
_{Agro-region: Denmark}

Bidens tripartita L.

Can be mistaken for

Characteristics

Cotyledons
Oval with entire leaf margins. Stalked. Smooth surface. Length approx. 10 mm.

True leaves
Egg-shaped outline. More or less deeply incised leaf margin. Stalked. The surface is smooth except close to the leaf base (and stalk). Length approx. 12-20 mm.

Mature plant
Trifid Bur-marigold is a medium-sized plant with a 20-60 cm high, erect stem. The plant is especially known by the 2 or 3 distinct, hooked Bristles on the fruit. The diameter of the flower head is approx. 10 mm. Seed production: Up to approx. 300 seeds per plant.

Seed
Compressed, oblong, wedge-shaped with sharp side edges and comb-shaped middle rib(s). The top end has 3 stiff, strong, harpoon-like, up to 3.5 mm long points, of which the middle one often is broken off. The surface is covered with downwards-facing, crystal-clear prickles on the side edges, top points and sometimes the middle rib; otherwise smooth. Thousand grain weight approx. 3.7 g.

Biology

Propagation and dispersal
Only through seeds.

Habit
Summer annual.

Importance

Trifid Bur-marigold is predominantly found on moist to waterlogged soil throughout Denmark. The species is mainly found in open and/or late sown spring crops and can cause severe losses especially in Beet.

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Taxonomy

Compositae.

Names in different languages

Danish :	Brøndsel, fliget
German :	Dreiteiliger Zweizahn
English :	Trifid Bur-marigold
Latin :	Bidens tripartita L.
Norwegian :	Flikbrønsle
Swedish :	Brunskära

Seedling

Early stage

Flower

Mature plant

Seeds

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Weed biology Agro-region: Denmark