Defeating Black/Stem Rust Of Wheat: A Guide For Successful Management

Is Wheat Black or Stem Rust posing a threat to the health of your precious wheat crops? 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 devastating disease that affects wheat crops worldwide. This fungal pathogen specifically targets the stems and leaves of wheat plants, leading to significant yield losses and economic damage. It is characterized 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 Infestation

The fungal pathogen spreads through the air, utilizing airborne urediniospores to infect neighboring wheat plants and even moves from one field to another. The primary source of inoculum can either originate locally, from nearby volunteer plants or be transported over long distances by wind.  

Scientific Name: Puccinia graminis f.sp. tritici 

Most Affected States

The exact distribution of black or stem rust of wheat in India is not well documented. However, it is known to be a serious disease of wheat and is likely present in wheat growing regions of the country. 

Symptoms of Wheat Black/Stem Rust

• The symptoms of wheat stem rust appear on almost all aerial parts of the plant, but we can see its 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, displaying a dark reddish-brown color 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, release of spores can be observed.
• As the infection progresses, the same pustules will start to produce teliospores.
• As teliospores production continues, the color of the pustule changes from rust color to black.
• When a significant number of pustules develop, the stem of the wheat plants become weakened, resulting in lodging.

Control Measures

If you have noticed any of the symptoms mentioned above in your wheat fields, it is imperative to take immediate action. Delaying intervention can lead to further spread and damage. Therefore, it is crucial to address the issue promptly and employ appropriate management strategies to control and mitigate the impact of wheat stem/Black rust on your crops. 

Cultural Measures

• Plant resistant wheat varieties like Lerma Rojo, Safed Lerma, Sonalika and Choti Lerma.
• Avoid applying excessive dozes of nitrogenous fertilizers.
• Practice good agronomic practices such as 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, mustard to break the disease cycle of black/stem rust.
• Early planting can help avoid the peak period of black/stem rust infection.

Mechanical Measures

• Remove and destroy the crop residues after the harvest.

Biological Measures

• Katyayani Organic Fungicide is all in one powerful product which controls all types of fungal diseases in plants. The recommended dosage is 1.5-2 gm per liter of water. Depending on disease incidence, repeat application at 7 to 12 days interval.

Chemical Measures

In case of severe infection, the spread and impact of 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
Zerox Fungicide	Propiconazole 25% EC	1 ml/lit of water
Tilt Fungicide
Dhanuka M-45 Fungicide	Mancozeb 75% WP	3 gm/lit of water
Amistar Fungicide	Azoxystrobin 23%SC	1 ml/lit of water
Godiwa Super Fungicide	Azoxystrobin 18.2% & Difenoconazole 11.4% SC	1 ml/lit of water
Borogold Fungicide	Nano Silver Particles & Peroxy Acid	1.5 gm/lit of water