Question

Wheat develops brown pustules on leaf sheaths and stems which later grow and turn blackish. They are caused by

• A. Ustilago tritici
• B. Puccinia striformis
• C. Puccinia recondida
• D. Puccinia graminis

Answer 1

The correct option is D Puccinia graminis

• There are three rust diseases that occur on wheat: stem rust, leaf rust and stripe rust. These diseases are each caused by a particular species of the “rust” fungus, Puccinia. Rust fungi all produce similar disease symptoms on the host plants and have similar requirements for infection. The diseases get their name from their appearance on the plant. Infection can occur on any above-ground plant part, leading to the production of pustules that contain thousands of dry yellow-orange to reddish-brown or black spores. These pustules give the appearance of “rust” on the plant.

• Stem rust (also known as black stem rust) is caused by Puccinia graminis f. sp. tritici. It is primarily a disease on wheat, though it can also cause minor infections on certain cultivars of barley and rye. Stem rust occurs primarily on stems but can also be found on leaves, sheaths, glumes, awns, and even seed. Symptoms begin as oval to elongate lesions that are generally reddish-brown in color.
  

So, the correct answer is 'Puccinia graminis'.