Originally published May 7, 2012
Late one afternoon this week I got a call to look at some “rice that looks like it is dying.” From a distance there were apparent rust colored areas of the field that corresponded to areas of the field that had remained dry longer than they should have. Close-up views exhibit one of the worst cases of blast I have seen since 1995 when it ripped through many Bengal fields. The variety here is CL261. We know it is susceptible to blast and have documented it in this variety since its release, but this is the worst case I have seen. The plants have about 3 crown nodes so it is much too early to apply any fungicide. Two more factors complicate the issue: first, it is a seed rice field; second it is in a field where soybean samples were shown to have aerial blight that is resistant to Quadris. In this case the preferred fungicide would be Gem applied at heading to control blast. Because Gem and Quadris are so closely related chemically something else will have to be applied to control sheath blight. A section 18 for a new fungicide has been applied for, but not granted yet. A few seasons ago a similar outbreak occurred in another variety because the field had dried out. This always aggrevates blast problems. A good deep flood is one of the best managerial things that can be done to at least lessen blast disease. It will not prevent it or control it, but it sure makes a difference in the severity of the disease.
Leaf blast lesion on rice
Area of rice field affected by leaf blast
The LSU AgCenter and the LSU College of Agriculture