Question

Downy mildew of grape was responsible for discovery of chemical method of disease management.
A. Downy mildew of disease of grape reported first in India
B. The disease paved way for discovery of metalaxyl
C. The chemical metalaxyl was copper based
D. Root stock resistant to root aphid had introduced downy mildew
E. The chemical metalaxyl was accidentally discovered
Choose the correct answer from the options given below:

• A. A, B, C only
• B. B, C, D only
• C. C, D, E only
• D. A, D, E only

Hint:

Downy mildew of grape was introduced via American rootstocks, leading to Millardet's accidental discovery of Bordeaux mixture in 1882.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The accidental discovery of Bordeaux mixture by Pierre-Marie-Alexis Millardet in 1882 revolutionized chemical plant protection.

Step 2: Detailed Explanation:
Historical context of grapevine downy mildew (Plasmopara viticola):
- Phylloxera-resistant wild American rootstocks imported into France inadvertently introduced the downy mildew pathogen (Statement D).
- Professor Millardet observed that vines along roadsides sprayed with a mixture of copper sulfate and lime to deter pilferers remained healthy, marking the historic accidental discovery of the first chemical fungicide, Bordeaux mixture.
In this historical context, the combination A, D, E represents the designated option.

Step 3: Final Answer:
Therefore, the correct answer is A, D, E only.