Question

The Irish potato famine that occurred in North Europe during 1845 was caused by-

• A. Alternaria solani
• B. Phytophthora infestans
• C. Synchytrium endobioticum
• D. Erwinia carotovora

Hint:

{Famine fact:} “Late blight = Phytophthora infestans”; “Early blight = Alternaria solani”. Keep late vs early straight to avoid mix-ups.

Answer 1

The Correct Option is B

Step 1: Identify the historic disease.
The mid-19th century Irish potato famine is historically linked to late blight of potato.
Late blight devastates foliage and tubers rapidly under cool, wet conditions.
Step 2: Name the causal organism.
Late blight is caused by Phytophthora infestans, an oomycete that spreads through sporangia and zoospores.
Step 3: Eliminate distractors.
Alternaria solani causes early blight, not the famine-scale late blight.
Synchytrium endobioticum causes wart disease of potato, a quarantine problem but not the famine agent.
Erwinia carotovora (now Pectobacterium) causes soft rot, mainly during storage and wounds.
Step 4: Conclusion.
Hence, the Irish potato famine was caused by Phytophthora infestans.