Crop Protection Online > Pests - Weed biology<br> <sub>Agro-region: Denmark</sub> - Lolium perenne L.
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18.6 2024 undefined

Weed biology
Agro-region: Denmark

Lolium perenne L. Previous page Next page

Go to identification key for weeds

Can be mistaken for

Lolium perenne L., ALS-resthat is morphologically identical but resistant to ALS-herbicides
Lolium perenne L., fop/dim-resthat is morphologically identical but resistant to fop/dim-herbicides
Lolium perenne L., metabolicthat is morphologically identical but has a metabolic resistance to a range of herbicides


Early stages
Folded vernation. The leaves seem soft and limp. The underside of the leaves are highly shiny. Small-toothed leaves. The ligule is short, approx. 1 mm. The lower leaf sheaths are often reddish purple.

Mature plant
Perennial Rye-grass is a medium-sized grass species with 20-50 cm high, erect, highly shiny stems. The awnless spikelets are joined in an open, oblong spike. The edge of the spikelets faces the straw unlike Couch-grass, where the surface of the spikelet faces the straw. Seed production: Up to approx. 150 seeds per spike.

Oblong, almost rectangular in outline. Awnless. The bract is 5-veined, slightly domed. The rachilla is short, flat and densely compressed and often sparsely toothed. Thousand grain weight approx. 2.0 g.


Propagation and dispersal
Mainly through seeds.



The species is frequently found at properties where it is part of the crop rotation as either roughage or seed crop. As a weed Rerennial Ryegrass can be found in all types of crops, where it can cause some losses at large densities. Perennial Rye-grass is undesirable in seed fields with Cocksfoot, Meadow Fescue and Red Fescue because it is difficult to separate the seeds.

For treatment options, consult 'Herbicides Across'.
For more options, consult 'Main Menu'.



Names in different languages

Danish : Rajgræs, alm.
German : Deutsches Weidelgras
English : Perennial Rye-grass
Latin : Lolium perenne L.
Norwegian : Raigras
Swedish : Engelskt Rajgräs

Lolium perenne L.: Very early stage
Very early stage
Lolium perenne L.: Early stage
Early stage
Lolium perenne L.: Ligule
Lolium perenne L.: Shiney leaf underside
Shiney leaf underside
Lolium perenne L.: Flowering spikelets
Flowering spikelets
Lolium perenne L.: Mature plant
Mature plant
Lolium perenne L.: Seeds

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