Question

Match List I with List II
List I:
A. Powdery mildew of mango
B. Bacterial wilt of cucurbits
C. Bacterial wilt of corn
D. Fire blight of pear, apple
List II:
I. Erwinia tracheiphila
II. Oidium mangiferae
III. Erwinia amylovora
IV. Pantoea stewartii
Choose the correct answer from the options given below:

• A. A-II, B-I, C-IV, D-III
• B. A-I, B-IV, C-III, D-II
• C. A-III, B-I, C-II, D-III
• D. A-I, B-II, C-III, D-IV

Hint:

To distinguish bacterial pathogens: Erwinia amylovora causes fire blight, Erwinia tracheiphila causes cucurbit wilt, and Pantoea stewartii causes corn wilt.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Plant pathogens (fungi and bacteria) cause destructive crop diseases.
Correctly identifying these pathogens by their scientific names is important for diagnosis and managing outbreaks.

Step 2: Detailed Explanation:
Let us analyze each plant disease and its causative agent:
1. Powdery mildew of mango (A): This fungal disease is characterized by white powdery growth on inflorescences, leaves, and young fruits.
It is caused by the obligate biotrophic fungus Oidium mangiferae (II).
Therefore, A matches with II.
2. Bacterial wilt of cucurbits (B): This systemic disease blocks the vascular system of squash, melons, and cucumbers.
It is caused by the bacterium Erwinia tracheiphila (I), which is transmitted by cucumber beetles.
Therefore, B matches with I.
3. Bacterial wilt of corn (C): Also known as Stewart's wilt, this disease causes leaf chlorosis and vascular wilting in maize.
It is caused by the bacterium Pantoea stewartii (IV) (formerly Erwinia stewartii), which is transmitted by the corn flea beetle.
Therefore, C matches with IV.
4. Fire blight of pear, apple (D): This bacterial disease causes blackening and wilting of blossoms, shoots, and leaves, giving them a scorched appearance.
It is caused by the bacterium Erwinia amylovora (III).
Therefore, D matches with III.

Step 3: Final Answer:
Combining these individual matches yields the sequence: A-II, B-I, C-IV, D-III.