Question

Which is a causal organism of the powdery mildew of mango?

• A. Xanthomonas campestris
• B. Oidium mangiferae
• C. Colletotrichum gloeosporioides
• D. Pestalotiopsis mangiferae

Hint:

Most powdery mildew fungi have an asexual conidial stage belonging to the genus Oidium.
Therefore, identifying the genus Oidium is a direct shortcut to finding the causal agent of powdery mildew in many crops.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Powdery mildew is a highly destructive fungal disease affecting mango (Mangifera indica), causing substantial yield losses by attacking the inflorescence (panicle), leaves, and young fruits.

Step 2: Detailed Explanation:
The causal organism of powdery mildew of mango is the biotrophic fungus {Oidium mangiferae (also classified as Erysiphe mangiferae in its sexual stage).
The characteristic symptoms of the disease include:
- The appearance of a white or grayish-white powdery growth (consisting of mycelia and conidia) on the inflorescence, flower buds, and young leaves.
- Infected flowers fail to open and drop off prematurely, preventing fruit set.
- Infected young leaves exhibit necrotic spots and curl upward.
Analyzing other options:
- Xanthomonas campestris pv. mangiferaeindicae causes bacterial canker of mango.
- Colletotrichum gloeosporioides is the causal agent of mango anthracnose, causing dark lesions on leaves and ripe fruits.
- Pestalotiopsis mangiferae is a fungus associated with grey leaf spot disease.

Step 3: Final Answer:
The causal organism of mango powdery mildew is Oidium mangiferae.