By Kaeley Kindrachuk, B.App.Sc, TechAg, Crops Extension Specialist, Outlook
We're nearing the time that scouting will come to an end for this year. However, there are still things to look for as we get closer to harvest and even afterwards. Crop stages across the province are different. As we get closer to crop maturity, here are some of the top things to watch for in canola.
Canola is one of the main crops where we still scout for insects and diseases as we get closer to maturity. While it may be too late to implement control measures for this year, they are good indicators as to what happened in the field and what to look for in the future. Some of the diseases that can significantly impact canola show up best later in the season, so it works well to scout for them closer to harvest.
Blackleg, sclerotinia and clubroot, if they are present in a field, will show up best at the end of the growing season; check any patches that appear to be lodging or ripening earlier than the rest of the field. When plants are fully podded, yet not completely dried down, examine the entire plant. Even if plants look healthy, diseases may still be present. Sclerotinia lesions will show up on the outside of the plant, starting in places where the petals drop on the plant. The lesions look like water soaked marks on the plant (Photo 1). When sclerotinia has infected the entire plant, you may see the sclerotia bodies inside the stem. Clubroot will show up on the plant’s roots. If it’s present at low levels, galls will start forming on lateral roots. If it’s present at higher levels, galls will form on the taproot, inhibiting the plants ability to uptake nutrients and water. Soil samples can be submitted to detect the pathogen through the soil testing program offered by SaskCanola and the Ministry of Agriculture.
While you are examining plants for sclerotinia and clubroot, clip the bottom of each stem at ground level to check for blackleg. If the plant is infected with blackleg, you will see black or brown within the cross-section of the stem (Photo 2). Blackleg may also show up visually on the outside of the stem as lesions dotted with pycnidia, which look like pepper sprinkled throughout the lesion. As you are scouting for diseases in canola, keep an eye out for insect damage as well. Damage from diamondback moth larvae, bertha armyworms and cabbage seedpod weevil may be visible. Just noting presence or absence may help guide your scouting in future years or give you or your clients a clearer picture of what happened during the growing season.
For more information on diseases in canola, or scouting at harvest, visit the ministry's diseases page or contact your nearest crops extension specialist.