Sheath blight is a significant disease in rice plants. This disease destroys the midrib, so it is necessary to open the planting canopy to find and recognize the condition. The disease causes plants to fall quickly. The earlier it falls, the greater the loss it causes. This disease causes the grain to be less filled or even empty. Sheath blight usually occurs when the plant begins to form tillers until just before harvest. However, this disease can also occur in young plants.
The disease is caused by the fungus Rhizoctonia solani, with early symptoms of pale white oval or round spots on the midrib. Under favorable (moist) conditions, the disease can reach the flag leaf. Pathogens survive and spread with the help of a resistant structure called the sclerotium.
This disease is challenging to control because the pathogen is polyphagous (has a vast host range). Plant fertilization with a dose of 250 kg urea, 100 kg SP36, and 100 kg KCl per ha can suppress the development of this disease. How to prevent the disease:
Source: Putra, R. (2018). Hama dan penyakit tanaman padi dan deskripsi padi sawah. Balai Pengkajian Teknologi Pertanian Kepulauan Riau.
Bacterial leaf blight (BLB) is a widespread bacterial disease and reduces yields by up to 36%. The disease occurs in the rainy or wet-dry season, especially in paddy fields that are constantly flooded and fertilized with high N (> 250 kg urea/ha). BLB disease produces two distinctive symptoms, namely crackle, and blight. Crackle is a symptom that occurs in plants <30 days old (nursery or newly moved). The leaves are gray-green, folded, and curled.
Cause: Unknown Red Stripe (URS) or Red Stripe (RS) is a relatively new rice disease that was first discovered in Subang, West Java, in 1987. This disease generally occurs in leaves, rice fields with poor drainage conditions, and plants that have reached the generative growth phase. This disease causes the grain is not to be fully filled or even empty. HDJ is negatively correlated with site height because the higher the site, the milder the disease.