Who reported that fire blight of pear was caused by a bacterium?

Correct option is C

The correct answer is (C) T.J. Burrill

Explanation:
• Thomas Jonathan Burrill, an American botanist, was the first to demonstrate in 1878-1882 that a plant disease could be caused by bacteria.
• He proved that 'Fire Blight of Pear' (and apple) was caused by a bacterium he named $Micrococcus$ $amylovorus$ (now known as $Erwinia$ $amylovora$).
• This was a groundbreaking discovery as, until then, bacteria were only thought to cause diseases in animals and humans (based on Pasteur and Koch's work).

Information Booster:
• $Erwinia$ $amylovora$ is a Gram-negative bacterium in the family Enterobacteriaceae.
• Fire blight gets its name from the blackened, 'scorched' appearance of the infected leaves and branches.

Additional Knowledge:
• Prevost (Option A): Proved in 1807 that bunt of wheat is caused by a fungus.
• E.J. Butler (Option B): Known as the 'Father of Indian Plant Pathology' and the first Director of the Imperial Mycological Institute.
• E.F. Smith (Option D): Often called the 'Father of Bacterial Plant Pathology' for his extensive later work and for winning the 'Fischer-Smith' debate over whether bacteria truly cause plant disease.