Question

which micro organisms responsible for causing rust and wheat

Answer 1

Wheat leaf rust is a fungal disease that affects wheat, barley and rye stems, leaves and grains 
rust in wheat = fungi

Answer 2

Wheat leaf rust is a common fungal disease in wheat, rye and barley. This disease affects, the stems, leaves and grains of these plants. 

The pathogen that causes the wheat leaf rust is the Puccinia rust fungus. The spread of this fungal disease is airborne. 

The three common types of the Puccinia fungus that causes wheat leaf rust are: 

i) Puccinia stiriformis  - causes yellow wheat rust

ii) Puccinia recondita  - causes brown wheat leaf rust

iii) Puccinia triticinia   - causes black wheat rust

- Wheat leaf rust can be controlled by varietal resistance and chemical means (use of triazole fungicides).