OCCURRENCE AND SURVIVAL OF PLASMODIOPHORA BRASSICAE IN FINNISH TURNIP RAPE AND OILSEED RAPE FIELDS
Clubroot, caused by Plasmodiophora brassicae is a serious plant disease of cruciferous plants. A field survey of occurrence of clubroot in turnip and oilseed rape fields was conducted in Finland in 1984-1989 and in 2007-2009. At present, the disease is distributed throughout the oilseed cultivation area. Clubroot was found on average from 22% of fields, but its severity was low; fields with high numbers of infected plants and plants with severe symptoms were rare. According to the survey, cultivation frequency of cruciferous plants is the most important factor affecting clubroot occurrence and severity. In a survival trial, clubroot declined to close to zero after four years in the absence of host plants, but traces of the pathogen were still detectable after a 19-year trial period. This means that the eradication of the pathogen is very difficult. Due to long survival of the pathogen and its distribution to entire cultivation area, clubroot is an important limiting factor in increasing the cultivation area of oilseed crops in Finland.
Rastas, M., Latvala , S. and Hannukkala, A. (2013). OCCURRENCE AND SURVIVAL OF PLASMODIOPHORA BRASSICAE IN FINNISH TURNIP RAPE AND OILSEED RAPE FIELDS. Acta Hortic. 1005, 627-632
clubroot, distribution, severity, crop rotation, field survey, bioassay