Crop residue affects Rhizoctonia solani population dynamics and seedling blight of canola.

Ahmed, H.U., Hwang, S.F., Turnbull, G.D., Strelkov, S.E., and Gossen, B.D. (2014). "Crop residue affects Rhizoctonia solani population dynamics and seedling blight of canola.", Plant Pathology, 13(1), pp. 50-55. doi : 10.3923/ppj.2014.50.55  Access to full text

Abstract

Seedling blight caused by Rhizoctonia solani Kühn substantially reduces stand establishment and seed yield of canola (Brassica napus L.) in western Canada. The effect of crop residue on soil populations of R. solani and canola seedling blight was examined under field, greenhouse and laboratory conditions. Field plots were established with inoculation or noninoculation with R. solani as the main plot and barley, canola, oat and field pea residues as the sub-plots. Soil samples were collected from each subplot for analysis in a greenhouse bioassay and laboratory assay of R. solani population before seeding canola. The crop residue effect was not significant. Under inoculation with R. solani, the yield was consistently greater when canola was grown on barley residue compared to the canola residue over two-year trials, although oat and pea residue contributed to greater yield. Without inoculation, canola yield was greatest when grown on barley residue, intermediate on oat and pea and the least on canola in the first trial and in the second trial greater yield was obtained on barley and oat residues compared to other residues. In the greenhouse bioassay, canola seedling emergence was greater, while damping off and root rot were less severe, following barley or oat compared to canola or field pea in both inoculated and non-inoculated treatments. Populations of Rhizoctonia were lower following barley or oat relative to canola or field pea. Crop rotation and incorporation of barley or oat residue between canola crops may be a useful strategy to reduce seedling blight of canola.

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