Given below are two statements
Statement I: American grapevine root stock helped the French farmers to control root aphids
Statement II: Root aphid resistant American root stock was also resistant to grapevine downy mildew
In light of the above statements, choose the most appropriate answer from the options given below
Statement I: American grapevine root stock helped the French farmers to control root aphids
Statement II: Root aphid resistant American root stock was also resistant to grapevine downy mildew
In light of the above statements, choose the most appropriate answer from the options given below
Show Hint
This highlights the importance of plant quarantine in modern agriculture.
- Both Statement I and Statement II are correct
- Both Statement I and Statement II are incorrect
- Statement I is correct but Statement II is incorrect
- Statement I is incorrect but Statement II is correct
The Correct Option is C
Solution and Explanation
The question refers to the historical "Great French Wine Blight" of the 19th century and the biological consequences of introducing plant material across continents.
Step 2: Detailed Explanation:
• Statement I Analysis: In the 1860s, the European grapevine (Vitis vinifera) was devastated by the Grape Phylloxera (Daktulosphaira vitifoliae), an aphid-like insect that attacks roots.
American grape species (like Vitis labrusca) had evolved with the pest and were resistant.
French scientists discovered that grafting European vines onto American rootstocks allowed the plants to survive the aphids. This saved the French wine industry.
Therefore, Statement I is Correct.
• Statement II Analysis: While the American vines provided resistance to Phylloxera, they were not resistant to all diseases.
In fact, the importation of these American vines introduced the pathogen Plasmopara viticola (Downy Mildew of grapes) to Europe.
The American vines often carried the pathogen without showing severe symptoms, but the European vines were highly susceptible.
Thus, Statement II is Incorrect.
Final Answer:
Statement I is a historical fact of successful biological control, whereas Statement II is false because the imported rootstocks actually brought new disease problems to Europe.
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