of tools and machinery in order to prevent the introduction of the pathogen to a disease-free field. It is not uncommon for an inattentive farmer or gardener to unknowingly carry in the pathogen after being previously exposed to it at a different time. One should avoid purchasing infected transplants of cabbage so as to prohibit the infestation of P. brassicae. Soil type is also an important factor in the development and spread of cabbage clubroot; the use of sand will allow for the plants to grow in well-drained soil, thereby eliminating the possibility of the pathogen to proliferate in a hospitable environment. Although it is difficult to eradicate the pathogen once it is introduced to a field, there are several methods for its control. Keeping the soil at a slightly basic pH of 7.1–7.2 by the addition of agricultural lime as well as the integration of crop rotation will reduce the occurrence of cabbage clubroot in already infected fields. Fumigation using metam sodium in a field containing diseased cabbages is yet another way to decrease the buildup of the pathogen. Control and management practices on already infected fields help to reduce the overall impact that P. brassicae has on a field of cabbage and other cruciferous plants, but it is extremely difficult to rid an individual plant of the disease once it is already infected. Importance Clubroot can be a reoccurring problem for years because it is easily spread from plant to plant. P. brassicae is able to infect 300 species of cruciferous plants, making this disease a recurring problem even with crop rotation. This wide host range allows the pathogen to continue its infection cycle in the absence of cabbages. Additionally, cabbage clubroot may be a stubborn disease due to its ability to form a microbial cyst as an overwintering structure. These cysts may last many years in the soil until it comes into contact with a suitable host, making it difficult to entirely avoid the introduction of the disease. Those growing cabbage need to be aware of the possibility of Plasmodiophora infestation by simply growing in particular fields that may have had cabbage clubroot previously. Canola infestation in Alberta In 2003 clubroot was identified in Alberta, Canada, as an outbreak in canola crops in the central area of the province mainly isolated to the Edmonton area. Clubroot is a soilborne disease caused by the biotrophic protist Plasmodiophora brassica.