Root rot: An ongoing challenge to pulse production on the Prairies.


Gossen, B.D., Chatterton, S., Conner, R.L., Chang, K.F., Pasche, J.S., McLaren, D.L., and Hwang, S.F. 2016. Root rot: An ongoing challenge to pulse production on the Prairies. Proc. 10th Can Pulse Res. Workshop, Winnipeg, MB, Oct. 27 28, 2016. p. 23.


When field pea, lentil and chickpea crops were first introduced onto the Canadian prairies in the 1970s and 1980s, they had relatively few disease problems. Unlike most foliar pathogens, the root rot complex was already present in Prairie soils, but has increased over time with repeated pulse cultivation. The root rot complex on pulses includes Fusarium spp., Pythium spp., Rhizoctonia solani Kühn and Aphanomyces euteiches Drechs. Aphanomyces euteiches has (likely) always been present in the Prairie region, but has recently been identified as the cause of severe damage in pea and lentil. In 2014 2015, A. euteiches was present in 40 50% of surveyed fields across the region. It is favoured by wet soils, but can cause injury under normal conditions when inoculum levels are high. Most of the pathogens in the root rot complex can be reduced using complex cocktails of seed treatments together with a 4-year crop rotation. However, no fungicides effective against A. euteiches have been identified, and normal cropping rotations are not very effective in reducing inoculum levels. No strong sources of resistance have been identified, but studies to identify the genes involved in partial resistance / tolerance are in progress. At present, the only reliable response to this pathogen is to avoid heavily infested fields. Molecular methods are being developed to rapidly identify fields with high levels of inoculum, and marker-assisted selection techniques are being developed to speed the selection of partially resistant cultivars.