Question

Mottle leaf of citrus is caused by the deficiency of

• A. Mo
• B. B
• C. Zn
• D. Cu

Hint:

Always associate Zinc (\(\text{Zn}\)) deficiency in Citrus with "mottle leaf" or "frenching," and in Rice with "Khaira" disease.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Micronutrient deficiencies in fruit trees often produce distinct, recognizable foliar symptoms that can be used to diagnose nutritional issues in the field.

Step 2: Detailed Explanation:
"Mottle leaf" (also known as frenching) is a classic zinc (\(\text{Zn}\)) deficiency symptom in citrus crops.
Because zinc is required for auxin (indole-3-acetic acid) synthesis and chlorophyll formation, its deficiency restricts cell elongation and disrupts leaf pigment development.
This results in small, narrow leaves with irregular chlorotic patches between the green lateral veins, producing a mottled appearance.

Step 3: Final Answer:
Therefore, mottle leaf of citrus is caused by a deficiency of Zinc.