Foliar diseases on oilseed rape

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Identification
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Foliar diseases on oilseed rape

This training program was created to help the user identify symptoms of leaf diseases on oilseed rape.

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Name of the fungusThe photos used in the training program and the identification of the diseases were realised and funded by the unit Bio3P (Biologie des organismes et des populations appliquée à la protection des plantes) of the INRA centre of Rennes and the CASDAR project AO 2005 number 391 Mise au point et utilisation d outils de biovigilance et de gestion durable des résistances variétales aux pathogènes (Creation and use of  tools for biovigilance and sustainable management of varietal resistances of pathogens), coordinated by the CETIOM in the framework of the UMT Pivert.

Identification of diseases

As a user, you will be shown pictures of disease symptoms on oilseed rape leaves. You will have to determine which fungus caused the observed symptoms. The different fungi dealt with and a summary of their symptoms are presented below (click on the photos to magnify them!):

Name of the fungus

Description of the symptoms

Example

Alternaria brassicae

Dark spots (diameter +/- 0,5 cm) showing circular zones of alternate light brown and dark brown colour. They are often surrounded by a halo of chlorotic tissue.
Example for Alternaria brassicae on oilseed rape

Leptosphaeria maculans

Ash-gray to beige spots, sometimes with an edge limited by a thin black margin. The black, well-delimited dots (pycnidia) are characteristic of L. maculans and visible to the naked eye. Old spots have a hole in the centre.
Example for Leptosphaeria maculans on oilseed rape

Leptosphaeria biglobosa

The spots are often darker than the ones caused by L. maculans. There is a small round spot in the centre, very often with a hole. A chlorotic halo is often visible. The pycnidia are small and barely visible to the naked eye.
Example for Leptosphaeria biglobosa on oilseed rape

Pseudocercosporella capsellae

Beige, paper-like spot. A more or less marked chlorotic halo is often visible.
 The spots can be uniformly beige or covered with irregular black dots (not to be confounded with pycnidia).
Example for Pseudocercosporella capsellae on oilseed rape

Pyrenopeziza brassicae

Beige, necrotic, paper-like spot. It is surrounded by small white films (acervula liberating the conidia) arranged in concentric circles around the necrotic tissues.
Example for Pyrenopeziza brassicae on oilseed rape

Mycosphaerella brassicicola

Black spot with a high density of black dots. A chlorotic halo is often visible.
Example for Mycosphaerella brassicicola on oilseed rape

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Date de modification : 25 avril 2023 | Date de création : 25 janvier 2014 | Rédaction : IPM network, contributor: Hortense Brun (INRA).