Rhizoctonia solani (AG-8): Surviving the summer after various winter crops

The effect of crop rotation and management practices on Rhizoctonia solani root disease and inoculum survival over two summers was examined in a 2-year paddock trial. In the first year (2011), there were treatments of barley, wheat, canola and chemical fallow, and in the second year (2012), barley plots of untreated, seed dressing (Dividend), in-furrow application of an unregistered fungicide or tilling to a depth of 10 cm below the seeding depth. Inoculum survival in five paddocks (two. canola, two wheat and one barley) was monitored over summer (February-June) 2013. In the 2-year trial, inoculum levels increased for cereals in the 2011 growing season, while for canola and fallow, they declined. Rhizoctonia root disease on barley roots ¡n 2012 were highest following barley. Inoculum levels ¡n cereals were significantly higher over summer 2012 compared with those for the canola and fallow plots Inoculum in the latter two plots had declined to below levels of detection at sowing in June 2012, while inoculum in the barley plots were significantly higher compared to the other plots. For the five paddocks, inoculum levels over summer is postulated to be affected by the previous crop and significant summer rainfall events A break crop of canola or a chemical fallow in paddocks with severe Rhizoctonia bare-patch, may reduce inoculum levels and reduce disease in the following cereal crop Barley exacerbates disease substantially compared to the other crops, so in paddocks with high levels of R solani inoculqm it is rçcommened that another crop is sown