Grain smut is a fungal disease that affects jowar (sorghum) crops, reducing both yield and grain quality. It is also known as covered smut or kernel smut. This disease is caused by a fungus called Sporisorium sorghi (formerly Sphacelotheca sorghi). If left unmanaged, grain smut can lead to yield losses of up to 25%.
Symptoms of Grain Smut of jowar
Grain smut is identified by the presence of spore-filled sacs called sori. These sori appear grayish-white to dark gray and look like elongated sorghum seeds. They are covered by a thin, papery membrane, which eventually ruptures, releasing black, powdery spores. Infected grain heads may show signs of:
- Distortion and discoloration
- Smutted kernels with abnormal growth
- Black spores when sori break open
Farmers can confirm the disease by carefully examining individual kernels and rupturing suspected sori to check for dark spores.
Cause of Grain Smut of jowar
The disease is caused by the fungus Sporisorium sorghi. This fungus spreads through:
- Infected seeds
- Airborne spores
- Wind, rain, and harvesting activities
Disease Cycle
- The disease starts when teliospores from ruptured sori spread through the air, rain, or contaminated seeds.
- These spores stick to healthy seeds during harvest.
- When infected seeds are planted, the fungus infects seedlings and remains inside the plant.
- As the plant grows, the fungus stays hidden until the reproductive stage.
- During grain formation, the fungus attacks the developing kernels, forming sori instead of normal seeds.
- The sori break open, releasing more spores and continuing the disease cycle.
Control Measures
To manage grain smut in jowar effectively, farmers should follow these steps:
1. Use Disease-Free Seeds
- Always plant clean, healthy seeds.
2. Seed Treatment
- Treat seeds with 0.5% formalin for two hours.
- Alternatively, soak seeds in 0.5-3.0% copper sulfate for 10-15 minutes before sowing.
- Apply fungicides like Captan, Thiram, Tebuconazole, or Agrosan GN.
3. Grow Resistant Varieties
- Plant resistant sorghum varieties like T29/1, PJ 7K, and CSH-9 to reduce the risk of infection.
4. Destroy Infected Plants
- Collect and properly destroy infected ear heads before they release spores.
5. Practice Crop Rotation
- Rotate sorghum with non-host crops to reduce fungal buildup in the soil.
Conclusion
Grain smut is a serious disease that can harm sorghum crops, but it can be controlled by using disease-free seeds, proper seed treatments, resistant varieties, and good farming practices. By following these measures, farmers can protect their crops and ensure better yields.
Please also Read: Citrus Canker Disease