Soil, climate, and management practices associated with the prevalence of clubroot in Colombia

Clubroot disease caused by Plasmodiophora brassicae is a major constraint for cruciferous crops in Colombia; however, information regarding its spread and the relationship between environmental and crop management practices with its occurrence in the country is scarce. This research established clubroot prevalence in the main cruciferous productive areas in Colombia and the relation of its occurrence with crop management practices, soil, and climatic characteristics. In total, 127 fields were visited along eight departments. Clubroot infestation was determined either by direct inspection of roots of host plants for clubroot symptoms or by report of previous observation of the disease symptoms by the farmers. Soil samples were collected for physical and chemical analysis, climatic information was obtained, and farmers were surveyed on the management practices of the production systems. The survey confirmed the presence of the disease in 53.6% of the visited fields. The only department where the disease symptoms were not observed nor reported was Nariño. A negative correlation was found between the disease occurrence and the content of aluminum in the soil, the number of days with rain per year, and the cultivation of clubroot-resistant hybrids. Moreover, a positive correlation was observed with the inclusion of cruciferous crops in the rotation scheme, the effective cation exchange capacity of the soil, soil pH, and the content of phosphorus, calcium, boron, and copper in the soil.