Question

Black (stem) rust of wheat is caused by

• A. Ustilago nuda
• B. Puccinia graminis
• C. Xanthomonas oryzae
• D. Alternaria solani

Answer 1

The Correct Option is B

To solve this question, we need to identify which organism is responsible for causing Black (stem) rust of wheat. This involves understanding the pathology of wheat diseases and identifying the causal organism for this specific condition.

Black stem rust of wheat is a plant disease caused by the fungus Puccinia graminis. It is one of the most significant diseases that affect wheat production, causing severe yield losses if not controlled. The disease manifests as reddish-brown pustules on the stems and leaves of wheat plants which later turn black, hence the name "Black rust."

Let's analyze the given options:

• Ustilago nuda: This fungus causes loose smut in barley and wheat, not rust.
• Puccinia graminis: This is the correct answer. It is responsible for causing Black stem rust in wheat.
• Xanthomonas oryzae: This bacterium causes bacterial blight in rice, not rust in wheat.
• Alternaria solani: This fungus causes early blight in potatoes and tomatoes, not rust in wheat.

Therefore, the correct answer is Puccinia graminis.

This knowledge is important for those studying agronomy, plant pathology, or preparing for exams involving agriculture-related questions, as understanding the diseases that affect crops can help in devising strategies for their management and control.