DiseasehighMay–Sep

Clubroot

Plasmodiophora brassicae

This description was machine-translated.

How to spot it

Clubroot is a soil-borne fungal disease caused by Plasmodiophora brassicae that affects all cruciferous plants. The pathogen enters through root hairs and causes the roots to swell into knobby, thickened outgrowths that block water and nutrient transport.

You recognize infection by wilting plants in sunshine, disturbed growth, and lack of head formation; when you dig up, the typical root swellings appear, which later rot. Spores remain viable in the soil for many years, so prevention is more important than late intervention.

Prevention

Use a long crop rotation and plant cruciferous crops at the same site no sooner than every 4 to 7 years. Improve heavy, acidic soils by liming and loosening structure, because a pH above 7 noticeably suppresses the pathogen. Remove infected plants with roots completely from the bed and do not compost them to prevent further spread of spores. Pay attention to clean origin of seedlings and soil, and clean tools and shoes after working in infected beds.