Clubroot

Clubroot is the name of a plant disease that is triggered by the pathogen Plasmodiophora brassicae. This is a parasitic living unicellular organism of the order Cercozoa that can attack the roots of most cruciferous plants. The host range includes crops such as cabbage, rapeseed, mustard and radish, ornamental plants and also a variety of weeds. Since the soil contamination by Plasmodiophora brassicae can last up to 20 years, the club root disease is considered the most profitable reducing disease in intensive cabbage cultivation.

Damage

Uncontrolled growth of cells leading to bulbous in the root zone, nodular, thickened bile. This bile lead to impairment or destruction of the root and vascular tissue. There is disruption of the nutrient and water supply ( wilting of the leaves ), which weakens the plant, that they die often under the influence of stress factors such as high evaporation at higher temperatures and associated water shortages.

Combat

Since the pathogen can survive for many years in the ground, are called " reduction strategy " agricultural cultivation technical countermeasures such as cultivation breaks (minimum 7 years), long-term crop rotation, good soil preparation to avoid waterlogging or the production of varieties of the species concerned with increased resilience and good root regeneration ability considered. Also, a neutral pH by liming is desirable ( pH > 7). A direct combat in the soil can be accomplished by the judicious use of calcium cyanamide.