The use of fluquinconazole fungicide applied as a seed dressing to canola before sowing was effective at reducing damage caused by the fungus Leptosphaeria maculans, commonly known as blackleg. When treated seed was sown under extreme disease severity (canola seed sown into canola stubble), the treated plants had lower levels of internal infection and lower plant mortality compared with untreated plants. When sown into a normal cropping rotation, the disease symptoms were still reduced by the seed treatment but there were only specific circumstances where grain yields were improved. Fluquinconazole increased the grain yield of cultivars with medium or lower levels of blackleg resistance at some sites but generally gave no advantage to cultivars that had high levels of blackleg resistance. The use of fluquinconazole is warranted when sowing canola into situations of high disease severity or when sowing cultivars with lower blackleg resistance.