Root rots have become a major factor limiting the yield of pulse crops in Manitoba and western Canada. In field pea, surveys in Manitoba in 2016 demonstrated that root rot was present in all fields with Fusarium spp. being detected in every field. Aphanomyces euteiches was identified in 58% of Manitoba pea fields. Similar results were observed in Alberta.
At present, there are no effective management strategies for root rot; no resistant cultivars are available, seed treatments do not provide full-season protection, and there are no in-crop fungicide products. One potential management strategy is to develop resistant pea lines. For pea, resistance has been identified and lines are being screened for resistance to Aphanomyces root rot. Markers associated with resistance are needed, so that resistance can be readily incorporated into new cultivars.
The cultivation of field pea cultivars with resistance to the most common cause of root diseases in Manitoba and western Canada will result in better economic returns to the producers, higher seed yields, more effective nitrogen fixation and greater inclusion of field pea in crop rotations.
Another management strategy is to avoid planting pea crops in heavily infested soils. Development of a soil test to categorize fields into low, medium or high risk fields based on levels of Aphanomyces inoculum is in progress. Refinement of this test to include multiple pathogens and improve the sensitivity of detection will benefit the pulse industry by ensuring that pea crops are planted in low risk fields, thus minimizing the risk of yield loss.