The blackleg epidemic in Canadian rapeseed as a "normal agricultural accident"

In an attempt to encourage the growth of a desired plant, humans transform various characteristics and surrounding ecological conditions, often giving rise to periodic plant disease epidemics. This paper uses the case of a blackleg epidemic caused by Leptosphaeria maculans in rapeseed in Canada to demonstrate that such epidemics may be seen as "normal accidents," i.e., the result of a particular set of social, natural and technical relations. The paper discusses how the pressures to increase the uniformity and productivity of rapeseed agriculture led to the creation of favorable conditions for the spread of blackleg in the crop. We argue that more proactive agroecosystems are needed in order to reduce the risk of normal accidents. We suggest that this may be achieved by developing and modifying legal frameworks for plant variety protection, farming practices (e.g., rotations, multilines), and organizations so as to emphasize greater variability rather than distinctness and homogeneity.