Is black rust of wheat posing a threat to your crop? Discover essential information and effective strategies to combat this fungal menace in this article!
Wheat black or stem rust, caused by the fungus Puccinia graminis, is a serious disease affecting wheat crops worldwide. It mainly attacks stems and leaves, causing heavy yield loss and economic damage. It is characterised by the appearance of black or dark brown raised pustules on the plant’s surface, which contain masses of rust-colored spores. If left unchecked, it can rapidly spread and decimate entire fields, making it difficult to control.
Type of Wheat Infestation
The pathogen spreads through the air using airborne spores, infecting nearby plants and even moving across fields. The primary source of infection may be local (from volunteer plants) or carried over long distances by wind.
Scientific Name: Puccinia graminis f.sp. tritici
Black Stem Rust of Wheat Symptoms
- The symptoms of wheat stem rust appear on aerial parts of the plant, but it has a greater occurrence on the stem, leaf sheaths and both upper & lower leaf surfaces.
- These symptoms primarily appear as oval to spindle-shaped pustules, known as uredial pustules or sori, with a dark reddish-brown colour resembling rust.
- The pustules rupture through the host’s epidermis and are often surrounded by damaged plant tissue.
- Due to the abundance of spores produced, the pustules possess a dusty appearance.
- When touched, the release of spores can be observed.
- As the infection progresses, the same pustules will start to produce teliospores.
- The colour of the pustule changes from rust colour to black.
- When a significant number of pustules develop, the stems of the wheat plants become weakened, resulting in lodging.
Black Stem Rust of Wheat Control Measures
If you have noticed any of the symptoms mentioned above in your wheat fields, it is imperative to take immediate action.
Cultural Measures
- Plant resistant wheat varieties like Lerma Rojo, Safed Lerma, Sonalika and Choti Lerma.
- Avoid applying excessive doses of nitrogenous fertilizers.
- Practice proper planting density, appropriate irrigation and timely weed control to reduce the black/stem rust incidence.
- Eradicate alternate hosts like Barberry and Mahonia spp.
- Follow mixed cropping and crop rotation with suitable crops like legumes and mustard.
Mechanical Measures
- Remove and destroy the crop residues after the harvest.
Biological Measures
- Katyayani Organic Fungicide is a powerful product to control all types of fungal diseases in plants. Use 1.5-2 gm per litre of water, and depending on disease intensity, repeat application at 7 to 12 day intervals.
Chemical Measures
In severe cases, the disease can be mitigated through the use of appropriate fungicides. Here are some commonly employed fungicides for managing black or stem rust in wheat:
|
Product Name |
Technical Content |
Dosage |
|---|---|---|
|
Propiconazole 25% EC |
1 ml/lit of water |
|
|
Mancozeb 75% WP |
3 gm/lit of water |
|
|
Azoxystrobin 23%SC |
1 ml/lit of water |
|
|
Azoxystrobin 18.2% & Difenoconazole 11.4% SC |
1 ml/lit of water |
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Frequently Asked Questions
What are the early symptoms of black stem rust of wheat?
Early Black Stem Rust of Wheat Symptoms include reddish-brown pustules on stems and leaves that later turn black.
How can I control black rust of wheat?
Use resistant varieties, follow crop rotation, and apply fungicides like Propiconazole or Mancozeb when needed.
Can seed treatment help control black rust of wheat?
Yes, proper seed treatment for wheat helps improve plant health and reduces early disease risk, though field control is also required.
