Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/2/2015
Publication Date: 11/1/2015
Citation: Zhou, X., Dou, F., McClung, A.M. 2015. Organic rice disease management using genetic resistance, cover crop and organic fertilizer. American Phytopathological Society Annual Meeting. 105(4):S4.159. doi.org/10.1094/PHYTO-105-11-S4.1.
Technical Abstract: The strong market demand for organic rice has driven the continued increase of organic rice production in the US. However, growers still lack effective tools to manage narrow brown leaf spot (NBLS) caused by Cercospora janseana and brown spot caused by Cochliobolus miyabeanus, two common diseases affecting organic rice production. An experiment was conducted in a field under organic management at Beaumont, TX in 2012, 2013 and 2014 to evaluate the impact of cultivar resistance, cover crop, and organic fertilizer on NBLS and brown spot severity and yield potential. Tesanai 2 had the highest resistance to both diseases followed by the hybrids XL723 and XL753 as compared to the susceptible cultivar Presidio. Production following the incorporation of clover winter cover crop resulted in a consistent reduction in NBLS and brown spot than following winter fallow. Production following ryegrass cover crop incorporation reduced NBLS in 1 of 3 years and brown spot in 2 of 3 years. An application of the soil amendment NatureSafe or Rhizogen at 90, 150 or 210 kg N/ha significantly reduced NBLS and brown spot compared to the nonamended control. Combined use of cultivar resistance (Tesanai 2), clover cover crop, and soil amendment at 150 kg N/ha provided the greatest reduction in both diseases and resulted in the highest rice yield. Cultivar, cover crop, and fertility rate are important factors for management of NBLS and brown spot diseases in organic rice production.