Sheath blight of rice

RiceSheathArk

Sheath blight of rice

Sheath blight of rice, caused by the fungus Rhizoctonia solani, is a devastating disease affecting rice crops worldwide. This fungal pathogen primarily targets the sheaths of rice plants, leading to significant yield losses if left unmanaged.

Symptoms

The symptoms of sheath blight typically manifest as elongated lesions on the leaf sheaths of rice plants. These lesions are initially light green and water-soaked, eventually turning brown and leading to the wilting and death of affected plant tissues. In severe cases, the disease can spread rapidly throughout the entire crop, causing extensive damage.

Disease Cycle

Rhizoctonia solani survives in the soil and plant debris, serving as a source of inoculum for new infections. The fungus infects rice plants through wounds or natural openings, such as leaf tips or nodes. Under favorable conditions of high humidity and moderate temperatures, the pathogen thrives and spreads rapidly within the crop canopy.

Management

Effective management strategies for sheath blight of rice include cultural practices, chemical control, and the use of resistant varieties. Crop rotation, proper drainage, and balanced fertilization can help reduce disease pressure. Fungicides can be applied preventively or curatively to control the spread of the fungus. Planting resistant rice varieties is also a key component of integrated disease management.

Economic Impact

Sheath blight of rice poses a significant economic threat to rice production globally. Yield losses due to this disease can range from 10% to 50%, depending on the severity of the infection and the susceptibility of the rice cultivars grown in affected areas. In regions where rice is a staple food crop, the impact of sheath blight can be particularly devastating.

Prevention

Preventive measures such as maintaining proper field hygiene, avoiding excessive nitrogen fertilization, and promoting good air circulation within the crop canopy can help reduce the incidence of sheath blight. Early detection of the disease through regular scouting and monitoring is essential for implementing timely control measures.