Integration of Brassica Cover Crop with Host Resistance and Azoxystrobin for Management of Rice Sheath Blight.

Sheath blight caused by Rhizoctonia solani is the most important rice disease that can cause significant losses in grain yield and quality in the southern United States. Current management options for sheath blight primarily consist of fungicides, tolerant cultivars, and cultural practices. These options are not always very effective. Brassica plants have been used for soil fumigation to manage a variety of different soilborne pathogens. In this field study, the efficacy of a Brassica juncea cover crop integrated with use of a tolerant rice cultivar and fungicide application was evaluated in 2011, 2012, and 2013. The B. juncea cover crop significantly lowered sheath blight severity in all 3 years and led to a significantly higher grain yield in 2013 as compared with the fallow control. 'Presidio' rice had lower sheath blight severity and higher yield than 'Cocodrie' in 2012 and 2013. Fungicide applications with azoxystrobin at the label rate (0.16 kg a.i./ha) or half the label rate (0.08 kg a.i./ha) significantly reduced sheath blight severity in all 3 years, resulting in a yield increase in 2 of the 3 years. B. juncea along with use of a tolerant rice cultivar and half the label rate of azoxystrobin can be an effective approach for management of sheath blight in rice.