Cargill Specialty Canola Program
Managing a transparent supply chain from seed to oil.
Protect your profits: scout your fields for blackleg and clubroot
Dr. Yu Chen
Plant Pathologist, Cargill
Just prior to harvest is one of the best times to scout your canola fields for yield-robbing diseases like blackleg and clubroot. These diseases can have a significant impact on yield and productivity and both are becoming increasingly common across western Canada.
For both blackleg and clubroot, the first and most important step is scouting. In order to build an appropriate and effective pest management plan, you must first determine the severity of the infection.
Although it is important to scout throughout the entire season, just before swathing is often the easiest time to detect diseases like blackleg and clubroot. Outlined below are the key steps in scouting for blackleg and clubroot as well as management strategies if either are identified.
SCOUTING FOR BLACKLEG
WHAT: Just before swathing, you are looking for stem lesions (with a white-grey centre possibly including tiny, hard black bodies plus a dark boarder) and cankers at the base. Stem cankers can cause premature lodging in severe cases.
HOW: Pull up the plant and cut the stem just below ground level -see photo below. Check numerous plants in at least 5 different locations in the field.
If blackleg is present, you will see discolouration and blackening of the stem. The amount of discoloration depends on the severity of the disease. You can refer to the scale on blackleg.ca to assess the severity of the disease in your field.
BLACKLEG MANAGEMENT STRATEGIES
If you identify blackleg in your field, there are multiple management strategies that can help you combat the disease.
1. ROTATION: Practice a diverse crop rotation, preferably three to four years between canola crops. Without a suitable host like canola, the disease cannot survive.
2. GENETIC RESISTANCE: Choose hybrids with a Resistant (R) blackleg field rating. The entire VICTORY lineup comes equipped with a durable polygenic blackleg resistance package which consists of multiple genes, with combinations of major and minor genes, providing protection at every growth stage from seedling to adult. Learn more about VICTORY polygenic blackleg resistance in the video below.