Brassica rapa
The major canola species that are susceptible to Alternaria Black Spot include "Brassica rapa" and "Brassica napus" (which are modified forms of rapeseed or brown mustard). The Canola Council of Canada has reported that "B. rapa" is more susceptible to the disease than "B. napus", because the latter has leaf wax, which provides more tolerance to black spot disease.