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[R] Brassica napus De Candolle variety oleifera (Brassiceae).
Fr: Colza; Ge: Raps; Pt: Colza; Sp: Colza; It: Colza.
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- Annual plant with racemes of yellow flowers (*) .
- The fruits are siliques (pods) enclosing small seeds, rich in lipids, that are used in oil production. Rape is also cultivated for green forage.
- Rape is sown in the autumn and develops, before winter, a taproot and a rosette of about 20 leaves. Stem extension begins with the return of the growing season (spring). Flowering begins before stem extension has finished and continues for more than one month.
- The phenological stages distinguished on this basis are: germination, seedling, rosette, stem extension, flowering and maturity (*) .
- Oilseed rape: the winter varities are the most cultivated. The seeds are harvested as dry as possible. After oil extraction, the protein-rich residues are made into oilseed cakes and used as animal feed. Oilseed rape has a potential market as a biological fuel.
- Rape is much less cultivated for forage use; there are winter varieties consumed in spring as well as summer (spring-sown) varieties.
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- Rape suffers from competition with weeds, especially grasses, which are significant nitrogen consumers. Herbicide treatments are essential.
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- Diseases: there has recently been an increase in economic importance of rape diseases cultivars currently in production. At the present time (1995), the problems, uniquely fungal diseases, are, in order of decreasing importance: Cylindrosporium concentricum,Pseudo-cercosporella capsellae, white rot, (Sclerotinia sclerotiorum) accompanied byBotrytis cinerea, Phoma lingam, leaf spot, (Alternaria brassicae), downy mildew (Peronospora brassicae), powdery mildew (Erisiphe polygoni) and clubroot (Plasmodiophora brassicae), which act over the entire vegetative cycle of rape, from the rosette stage until maturity.
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- Principal European pests: they are very numerous and crops often require treatment. The cabbage stem flea beetle (Psylliodes chrysocephala) and the turnip flea beetle (Phyllotreta atra) attack the young plants. The rape beetle (Meligethes aeneus) and the pollen beetle (Meligethes viridescens) attack the flower buds and can cause serious damage in the spring, especially in spring rape. The rape stem weevil (Ceuthorhynchus napi), the cabbage seed weevil (C. assimilis) and the brassica pod midge (Dasineura brassicae) attack the pods. The cabbage aphid (Brevicoryne brassicae) can cause incomplete flower development and discoloration.
The field slug (Deroceras reticulatum), and the cabbage root fly (Delia radicum) are also significant pests.
There are many other pests that may cause more minor damage. The peach-potato aphid (Myzus persicae) and the black bean aphid (Aphis fabae) deform the leaves. The wood pigeon (Columba palumbus) eats the leaves. The rape winter stem weevil (Ceuthorhynchus picitarsis, Gyllenhal, Col., Curculionidae) destroys the terminal bud during early stem extension growth.

[R] Images

* Rapeseed (Minost C.)
1: plantlet.
a: cotyledons; b: first leaves.
2: flowered stem.
a: leaf; b: yellow flowers disposed in a bunch; c: fruit (pod).

* Phenological stages of rapeseed (Minost C.)
A: emergence; B: plantlet; C: rosette; D: "boot" stage; E: flowering; F: maturity.

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HYPPZ on line: Species (scientific names), Pests (common names), Glossary, Crops.

HYP3 : HYPP Phytopathology.

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