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

Crop Protection Online

26.4 2024

Weed biology
_{Agro-region: Denmark}

Senecio jacobaea L.

Can be mistaken for

Characteristics

Cotyledons
Egg-shaped with entire leaf margins. Stalked. Smooth surface. Length approx. 6 mm.

True leaves
Circular to broad egg-shaped with slightly sinuate or lobed leaf margins. Stalked. Sparsely hairy on the top side and smooth on the underside. Length approx. 8-10 mm. Later true leaves are more broadly lobed. The first true leaves on plants that are germinated from rootstock resemble the true leaves of young seedlings.

Mature plant
The plant is relatively high with a 40-80 cm high, erect stem. The leaves are more lobed/curly than those of Spring Groundsel. The heads are joined in a dense, terminal corymb unlike Spring Groundsel, which has more open corymbs. Unlike Common Groundsel Common Ragwort has distinct, long and protruding ray corollas. Seed production is not known.

Seed
Stick-shaped, longitudinally ribbed with a round or oval, toothed cross section. The surface has upwards-turned barbate hairs between the ribs. Thousand grain weight is not known.

Biology

Propagation and dispersal
Only through seeds and rootstock.

Habit
Perennial.

Importance

Common ragwort is found especially on set-aside, in hedgerows and by roadsides. In recent years the plant has increasingly dispersed from the many set-aside fields to neighbouring meadows. There, it is a serious problem because the plant is very poisonous and may lead to severe cases of poisoning in livestock.

For treatment options, consult 'Herbicides Across'.
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Taxonomy

Compositae.

Names in different languages

Danish :	Brandbæger, eng
German :	Jakobsgreiskraut
English :	Common Ragwort
Latin :	Senecio jacobaea L.
Norwegian :	Landøyda
Swedish :	Stånds

Seedling

Early stage

Flower head

Mature plant

Seeds

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Weed biology Agro-region: Denmark