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Oral: Biological and Cultural Disease Management


Organic rice disease management research in the United States
X. ZHOU (1), X. Zhou (1) (1) Texas A&M AgriLife Research, U.S.A.

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Organic rice production has steadily increased in the U. S. over the last 20 years, with a majority of acreage being grown in the southern region. Due to warm and long growing seasons in the region, diseases are among the most important factors threatening the sustainability and productivity of organic rice. Field studies were conducted for the first time in the U. S. to evaluate the efficacy of cultivar resistance, cover crop, fertility, tillage and biocontrol agent for management of rice diseases on organically managed land in Texas in 2009 to 2014. Among 20 cultivars evaluated, Tesanai 2 had the highest level of resistance to both narrow brown leaf spot (NBLS) and brown spot followed by XL723 and XL753. Production following the incorporation of clover winter cover crop resulted in a consistent reduction in NBLS and brown spot than following winter fallow or annul ryegrass cover crop. An application of the soil amendment Nature Safe or Rhizogen at 90, 150 or 210 kg N/ha significantly reduced NBLS and brown spot. Use of conventional tillage practice prevented the occurrence of straighthead on all 20 cultivars evaluated in the clover winter cover crop plots. A foliar application of Serenade Max significantly reduced NBLS and sheath blight, resulting in an increase in yield. Cultivar resistance, cover crop, fertility, tillage and biocontrol can be effective tools for management of diseases in organic rice production.