Characterization of the Virulence and Yield Impact of Species on Canola ().

Multiple species of can contribute to the development of root rot in canola (), making disease management difficult. We conducted field and greenhouse experiments to investigate the impacts of and , and the interaction between and on root rot severity and canola yields. Inoculation with any of the three spp. resulted in significant disease severity and reduced seedling emergence compared with non-inoculated controls, leading to yield reductions of up to 35%. Notably, there was a strong correlation ( = 0.93) between root rot severity at the seedling stage and at maturity. Regression analysis indicated a linear decline in seedling emergence with increasing disease severity. Furthermore, disease severity at maturity adversely affected the pod number per plant and the seed weight per plant, with both parameters ultimately approaching zero at a severity of 4.0 on a 0-4 scale. Co-inoculation with and induced more severe root rot than inoculation with each species on its own, suggesting synergistic interactions between these fungi. Knowledge of these interactions and the relative virulence of spp. will contribute to the improved management of root rot in canola.