Rust- Plant Fungal Disease

Rust- Plant Fungal Disease

  • Plant diseases caused by pathogenic fungi.
  • Pucciniales (previously also known as Uredinales).






Rusts hosts

  • Apple
  • Pear
  • Wheat
  • Barley
  • Rye

Infection area

  • Leaves
  • Petioles
  • Tender shoots
  • Stem
  • Fruits
  • Rusts are named after the reddish rusty looking sori and the disease is usually noticed after rain.
  • The group contains pathogens that have a harmful effect on agriculture, forestry, and horticulture.
  • These fungi have significant concerns and a short number of factors to cultivate agricultural and forestry crops successfully.

Fungal spore

Obligate parasite


Asexual spores



  • When airborne spores settle on a plant, weak hydrophobic interactions are formed with the cutin on the plant cell surface, securing it.
  • By a process not fully understood, the production of mucous-like substances called ‘adhesions’, initially sticks the spore to the plant surface.

Rust- Plant Fungal Disease

Image Source: The Ohio State University


  • Wheat is the most important grain crop, a staple food for more than one-third of the world population.
  • In Pakistan wheat mostly occur in the areas of Punjab as well as Sindh.
  • However, in Sindh, the wheat yield per hectare is higher as compared to Punjab.
  • In cereal crops, if we rank the crop in the counting are rice only in production and acreage.
  • Wheat crop are susceptible to a number of diseases, due to these diseases overall production of wheat is reduced to a great extent.
  • Because in all-natural environments and in all stages of growth are subject to various Mechanical, Physiological and Biological stresses that interfere with their normal growth and development.
  • Weather, primary hazards for wheat production are weeds, bacteria, fungi, nematodes, viruses, insects, pollutants, toxicants.

Black stem rust of wheat

Causative Organism: Puccinia graminis var. tritici


  • Long and narrow streaks or pustules are formed on all green parts of the plant vie:
  • Stem
  • Leaf
  • Sheath
  • leaves
  • Ear heads.

The color of the small blister (pustules) in the start are brick red and when the season is end or plants become mature the color change into black.

The rate of development of the disease is high during moisture and hot weather that usually appear during the heading stage.

Leaf rust of wheat (orange rust)

Causative Organism: Puccinia recondite


  • A small blister is formed dispersed chiefly on the leaves surface of plants, very rare elsewhere.
  • The color of the pustules, in the beginning, are brown/orange and when the plant becomes mature the color change into black.
  • Moisture and moderate temperature (18-20C) is favorable for the spreading and development of this disease, which appears in the form of stem or black rust.

Yellow or stripe rust of wheat

Causative Organism: Puccinia striiformis

Symptoms: Very small (smaller than in orange rust) pustules are formed in stripes on leaves and all green parts of the plants.

  • These pustules are bright yellow, these pustules appear bright yellow at the start of the disease and when the plant becomes mature the color change into black.
  • Moisture and cold weather (about 15C) favor the diseases.
  • It is the first of the three rusts that appear on wheat.
  • The record showed that there are many severe attacks of black stem rust of wheat in 1906-1908 at Mirpurkhas, Sindh;
  • yellow/stripe and orange/leaf rust of wheat in 1978 at all over the wheat-growing areas of Pakistan.
  • Among plant diseases, the disease caused by Puccinia striiformis (stripe or yellow rust) is a wheat crop foliar disease that has significant importance.
  • The result of this disease is heavy economic losses throughout the world.
  • The strength of loss mainly depends on the resistance level of the germplasm.
  • In the case of extremely susceptible varieties, losses may increase rapidly as high as 80%.



Internet Sources

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Rust- Plant Fungal Disease

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