Entomology and Plant Pathology, Oklahoma State University
127 Noble Research Center, Stillwater, OK74078
Vol. 11, No. 38
Oct 18, 2012
Update on Black Leg Disease of Canola
John Damicone, Extension Plant Pathologist
Black leg causes both leaf spots (Fig. 1) and stem cankers (Fig. 2) on canola plants. The leaf spot phase of the disease itself does not cause yield loss, but damaging stem cankers, capable of reducing yield by up to 50%, develop at the base of stems on leaf scars where infected leaves were attached. Black leg was first identified in canola in 2009 in a field in northern Oklahoma. Since then the disease has been found in most areas where canola is grown.
Fig 1. Leaf spot phase of black leg disease of canola.
Fig 2. Stem canker phase of black leg disease of canola.