Sheath blight and blast cause significant rice yield and quality reductions every year that cost Mid-South farmers millions of dollars. Disease resistance is the best control, but often it is not available or breaks down after varietal release. Many of our long-grain varieties are susceptible to sheath blight, and several major varieties are susceptible to blast.

Cultural control can reduce disease development, but is not all ways completely effective. As a result, rice farmers often rely on fungicides to control diseases. Several new fungicides are available, and rate and timing are critical for maximum return. Each disease has its own cycle, and control practices are effective only at certain stages when the pathogen is susceptible to the chemical control and before damage occurs.





Later timings (10 to 15 days) are more detrimental than late sheath blight timings.

Donald E. Groth is the rice pathologist at LSU AgCenter's Rice Research Station. e-mail: