P.A. Millardet discovered a fungicide which was effective against which disease and name of the fungicide:

Correct option is D

Pierre-Marie-Alexis Millardet, a French botanist, is credited with the discovery of the first widely used fungicide in the world — Bordeaux Mixture — in 1885. This discovery was a landmark event in the history of plant pathology and plant protection.
�� Why (d) is the Correct Answer:
· Disease Targeted:
· The fungicide was formulated to control Downy Mildew (Plasmopara viticola), a devastating disease affecting grapevines in France.
· Origin of the Discovery:
· Millardet observed that grapevines sprayed with a mixture of copper sulfate and lime (used to deter vineyard thieves) remained healthy while unsprayed ones were affected by the disease.
· This observation led to scientific testing and formulation of what is now known as Bordeaux mixture.
· Composition:
· Copper sulfate + Lime + Water — the lime reduces phytotoxicity of copper and improves adherence to plant surfaces.
· Significance:
· Bordeaux mixture became the first fungicide used globally and laid the foundation for modern chemical disease control in agriculture.