Question

Which of the following plant disease was responsible for environmental disturbances impacting even the wildlife

• A. Late blight of potato
• B. Chestnut blight
• C. Downy mildew of grapevine
• D. Southern Corn blight

Hint:

Foundation species are organisms that play a vital role in structuring a community.
When a pathogen targets a foundation species (like the American Chestnut), the ripple effects are felt throughout the entire food web.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks to identify a plant disease that had such a massive ecological footprint that it altered entire forest ecosystems, thereby affecting wildlife and the broader environment. This refers to a "keystone" plant species being decimated by a pathogen.

Step 2: Detailed Explanation:

• Chestnut Blight (B): Caused by the fungus Cryphonectria parasitica, this disease was introduced to North America in the early 20th century.
Before the blight, the American chestnut (Castanea dentata) was a dominant "foundation" tree in eastern forests, making up nearly 25% of the hardwood canopy.
Chestnuts provided a critical, consistent food source (mast) for a vast array of wildlife, including bears, deer, squirrels, and birds.
The rapid death of billions of trees completely restructured forest compositions and eliminated a primary food source for wildlife, leading to significant environmental disturbances.

• Other Options:
- Late Blight (A): While it caused the Great Irish Famine and massive human suffering, its primary impact was on an agricultural monoculture (potato) rather than a natural forest ecosystem affecting wildlife.
- Downy Mildew (C): Impacted the European wine industry significantly but did not lead to large-scale forest ecosystem collapse.
- Southern Corn Blight (D): A significant agricultural epidemic in 1970 due to genetic uniformity (T-cytoplasm) but was contained within the agricultural sector.
Final Answer:
Chestnut blight is the classic example of a plant pathogen causing widespread environmental and wildlife disturbance.