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

Crop Protection Online

1.12 2024

Weed biology
_{Agro-region: Denmark}

Polygonum lapathifolium L.

Can be mistaken for

Polygonum persicaria L., of which the true leaves have an almost smooth surface.

Characteristics

Cotyledons
Oblong to oval with entire leaf margins. Stalked. Sparsely hairy surface. Length approx. 10 mm.

True leaves
Lancet-shaped with entire leaf margins. Unstalked. Densely hairy surface. Length approx. 15-35 mm.

Mature plant
Pale Persicaria is a medium-high to high (25-80 cm), erect plant. It is known by its spike-shaped inflorescences. In contrast to Redshank only few of the true leaves have a black spot. The diameter of the flower is approx. 2 mm. Seed production: Up to approx. 800 seeds per plant.

Seed
Almost heart-shaped and flattened from the sides. The surface is smooth, often showing remnants of the perianth. Thousand grain weight approx. 3.6 g.

Biology

Propagation and dispersal
Only through seeds.

Habit
Summer annual.

Importance

The species is frequently found in spring-sown crops throughout Denmark, but can also be found in autumn-sown crops. It thrives in waterlogged soil and can cause large yield losses, even in competitive crops such as cereals and Oil-seed Rape.

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Taxonomy

Polygonaceae.

Names in different languages

Danish :	Pileurt, bleg
German :	Ampferknöterich
English :	Pale Persicaria
Latin :	Polygonum lapathifolium L.
Norwegian :	Raudt hønsegras
Swedish :	Vanlig pilört

Seedling

Early stage

Flower

Mature plant

Seeds

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Weed biology Agro-region: Denmark