Powdery mildew of Beets

Erysiphe betae

Erysiphe betae is a plant pathogen. It is a form of powdery mildew that affects sugar beet. The fungus occurs worldwide in all regions where sugar beet is grown and it also infects other edible crops, e.g. beetroot.
 
Description
This fungus has a white powdery appearance. It appears on leaves in the summer time. Infection normally begins on older leaves, typically close to the junction between the lamina and petiole, and it develops on both ab- and adaxial surfaces.
 
Pathogenicity
This pathogen decreases yields in crops by the reduction of chlorophyll in the leaves of plants. This will affect (as was mentioned) the yield and the quality of the seed crops. It also causes leaf and shoot deformities. In the case of Erysiphe betae, entry into the cell is both mechanical penetration and enzymatic degradation of the cuticle and the cell wall.
 
Plant defenses
The way that plants deal with these enzymes is they have an array of specialized inhibitors that counteract the effects of that specific pathogen. Some of these degrading enzymes include pectin lyases and polygalacturonases. In the case of when the pathogen gets entry through mechanical means the plant in itself doesn’t have much it can do against this kind of attack.

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