Canola School: Lodged, Dead or Thin Canola Stands — Scouting for Blackleg & More

Episodes:

There’s a lot you can learn from late season scouting of canola. Not only is this prime insect feeding time, it’s also when disease development reaches its peak. Prematurely ripened areas in a field should be a giant red flag to any farmer or agronomist. What are you looking for? It could be sclerotinia, blackleg, or, worse yet, clubroot. It makes a significant difference to ensure you identify the offending disease, because each of these requires a very unique long-term management plan. While souting for maturity, or even while swathing, is a great time to assess what’s killing your canola.

When assessing a crop for blackleg, early scouting is essential. A fungicide application very quickly becomes a waste of money, as staging progresses past even the four-leaf stage. But, there’s still good reasons to scout, even into and after harvest.

Symptoms of blackleg at later stages of crop development will include: lodging, characteristic legions on the leaves and internal blackening of the stem. Residue, even two years following a canola crop, can give an indication of blackleg pressure as well, with the presence of pycnidia (reproductive structures, or “fruiting bodies”). A quick scout of a field can give you an idea of blackleg pressure in the future, and resistance breakdown in your area.

In this video, Ralph Lange of Alberta Innovates Technologies Futures, discusses the importance of continual scouting for blackleg and how to diagnose the disease (and differentiate blackleg from sclerotinia). Lange also reminds us that variety-selection and rotation is a crucial step in mitigating the risk of resistance breakdown.

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