Root rot suspected in wet Manitoba field

2010 - Issue 12


 

An agronomist from Oakville, Manitoba, was called out to a Roundup Ready canola field in sandier soil. Many canola plants throughout the field were bent and growing horizontally. The plants could be plucked out of the ground without any effort, and their tap roots had no hairs.

Based on the minimal root development and lack of root hairs, it could be brown girdling root rot — especially since it was spread throughout the field and that the area has had excess water. BGRR is rarely seen outside of the Peace region, so tests will need to be done to confirm. Nothing can be done to control it other than avoiding short rotations — but this is no guarantee. Argentine canola is much more resistant to the adult plant root rots than Polish, but with the right conditions it still can be a problem.

When making an assessment on the cause of damage:
—Look for insect damage or above-ground disease. No lesions or bite marks were noticed on this crop.
—Consider herbicide damage. For this field, the previous crop was wheat (spayed with Everest) and the crop showed no group 2 injury symptoms (purpling, clumping, abortions of flowers.) Look for patterns in the field that would suggest drift.
—Consider nutrient deficiency. This field had good levels of applied fertilizer, no deficiency symptoms were seen, and damage was spread throughout the field.

 

Canola Watch