For the first time who reported that a plant disease (fire blight of pear) was caused by bacterium (Erwinia amylovora) in 1882

Answer: Option D

For the first time, T. J. Burrill reported that a plant disease (fire blight of pear) was caused by a bacterium (Erwinia amylovora) in 1882.
The first studies on bacteria as plant disease agents were carried out by T. J. Burril in 1878 and concerned the fire blight disease of apples and pears, caused by Erwinia amylovora.
Fire blight is a contagious disease affecting apples, pears, and some other members of the family Rosaceae. It is a serious concern to apple and pear producers.
The causal pathogen is Erwinia amylovora, a Gram-negative bacterium. It is a short rod with rounded ends and many peritrichous flagella.