Diseases

Powdery mildew of swede

Brassica napus L. var. napobrassica (L.) Rchb.

A fungal disease of swede caused by the pathogen Erysiphe cruciferarum. It is characterized by the appearance of a whitish coating on the leaves, leading to leaf deformation, yellowing, and general stunting of the plant.

In the reference 9 varieties crop Rutabaga, where this is mentioned in the description.

The causative agent of the disease is the specialized fungus Erysiphe cruciferarum, which infects a wide range of Brassicaceae species. A characteristic whitish-gray coating, consisting of mycelium and conidia, forms on the surface of the leaf blades and gradually becomes denser over time. The spots may coalesce, eventually covering the entire leaf area.

As the disease progresses, the leaves turn yellow, become deformed, and wither prematurely. By the end of the growing season, cleistothecia—small black fungal fruiting bodies—often form on the affected areas. Disease development is favored by a combination of moderate temperatures and periods of plant stress, such as drought or excessive humidity. Specific resistance genes to this pathogen in swede have not yet been described, and breeding programs currently utilize only accessions with varying degrees of field resistance.

General information about the subject — on the page Powdery mildew.

Sources8

Varieties of Rutabaga mentioned in the description

Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.