Rice false smut: TNAU releases methods to prevent and manage the disease in plants
Coimbatore: Rice false smut is a fungal disease caused by Ustilaginoidea virens. The disease is now widely prevailing in delta districts in matured plants. Normally few grains in a panicle are infected by this fungus and infected grains are converted into a velvety, yellow mass of fruiting bodies. The smut ball appears small at first and grows gradually up to the size of 1 cm. It is seen in between the hulls and encloses the floral parts.The colour turns to greenish black with a velvety appearance when the grain matures. However, now the disease has become a major one causing significant yield loss.
Flowering stage is the most susceptible stage for infection by the fungus. Presence of rain and high humidity during flowering stages predisposes the rice crop to infect by U. virens. Presence of high nitrogen in soil and strong winds favour release and dissemination of the pathogen spores to neighbouring fields. Late planting is an important factor which favours the spread of this disease.
The disease can be managed through
Preventive methods
-Seed treatment with carbendazim @ 2gm/kg of seed.
- Removal and destruction of infected grains in the early stages of the disease.
- Split application of nitrogenous fertilizers.
Cultural methods
- Early planting is recommended in endemic areas.
- Field activity such as intercultural operations should not be carried out when the plants are wet.
- Proper removal and disposal of smut balls prior to harvest helps to reduce build-up of primary inoculum for the next season in the field.
Chemical methods
- Two foliar sprays with propiconazole 25 EC @ 500 ml/ha or copper hydroxide 77 WP @ 1.25 kg/ha at boot leaf and 50% flowering stages are effective in managing this disease.
Flowering stage is the most susceptible stage for infection by the fungus. Presence of rain and high humidity during flowering stages predisposes the rice crop to infect by U. virens. Presence of high nitrogen in soil and strong winds favour release and dissemination of the pathogen spores to neighbouring fields. Late planting is an important factor which favours the spread of this disease.
The disease can be managed through
Preventive methods
-Seed treatment with carbendazim @ 2gm/kg of seed.
- Removal and destruction of infected grains in the early stages of the disease.
- Split application of nitrogenous fertilizers.
Cultural methods
- Early planting is recommended in endemic areas.
- Field activity such as intercultural operations should not be carried out when the plants are wet.
- Proper removal and disposal of smut balls prior to harvest helps to reduce build-up of primary inoculum for the next season in the field.
Chemical methods
- Two foliar sprays with propiconazole 25 EC @ 500 ml/ha or copper hydroxide 77 WP @ 1.25 kg/ha at boot leaf and 50% flowering stages are effective in managing this disease.