Brown leaf spot rice is one of the most serious diseases that can affect a growing rice crop. It usually begins with leaf spot on young leaves and, if not treated properly, it can decrease yield substantially. If you’re growing a crop of rice, you’ll do well to keep an eye on the leaf spots.
About Rice with Brown Leaf Spots
Brown spots on rice can start on even seedling leaves and are usually small, round to oval circles, brownish in color. It is a fungal issue, caused by Bipolaris oryzae (previously known as Helminthosporium oryzae). As the crop grows, leaf spots may change colors and vary in shape and size, but are usually round.
Spots are often a brownish red as time progresses but usually begin just as a brown spot. The spots also appear on the hull and leaf sheath. Older spots may be surrounded by a bright yellow halo. Don’t confuse with blast disease lesions, which are diamond shaped, not round, and require different treatment.
Eventually, rice kernels are infected, creating a minimal yield. Quality is affected as well. When glumes and panicle branches become infected, they often show black discoloration. This is when kernels become most thin or chalky, not filling properly and yield is largely reduced.
Treating Brown Leaf Spot of Rice
The disease develops largely in areas with high humidity and on crops planted in nutrient deficient soil. This infection occurs when leaves remain wet for 8 to 24 hours. It most often happens when the crop is planted from infected seeds or on volunteer crops, and when weeds or debris from previous crops is present. Practice good sanitation in your fields to help avoid brown leaf spot of rice and plant disease-resistant varieties.
You may also fertilize the crop, although this can take several growing seasons to work completely. Take a soil test to learn exactly which nutrients are missing in the field. Incorporate them into the soil and monitor them regularly.
You can soak seeds before planting to limit the fungal disease. Soak in hot water 10 to 12 minutes or in cold water for eight hours overnight. Treat seeds with a fungicide if you’re having problems with rice with brown leaf spots.
Now that you’ve learned what is rice brown leaf spot and how to properly treat the disease, you may increase the production and the quality of your crop.