Economic Loss from Rhizoctonia Bare Patch in Rainfed Winter Wheat and Spring Barley in Oregon

Economic loss from Rhizoctonia bare patch, caused by Rhizoctonia solani AG-8, was estimated in two 50-ha fields on a single farm. A winter wheat crop was managed as a conventionally cultivated 2-year wheat/fallow rotation and a spring barley crop was managed as a no-till annual crop. Aerial photographs revealed that the patch-affected area was nearly double in barley (17%) compared with wheat (9%). Yield inside patches was reduced by 73 and 68% for wheat and barley, respectively. Grain produced on each field was reduced more for winter wheat (21.6 metric tons [t], valued at US$5,080) than for spring barley (16.8 t, valued at US$2,784). More precise estimates of economic damage and more robust management practices for Rhizoctonia bare patch must be developed.