Which one of the following is linked to the discovery of Bordeaux...

Bordeaux mixture was discovered by Millardet in France in 1882 . It is prepared by dissolving $40 \mathrm{~g}$ of copper sulphate and $40 \mathrm{~g}$ of calcium hydroxide in $5 \mathrm{~L}$ of water. It was first used to control downy mildew disease of grape-vine that is caused by a fungus Ptasmopara viticota. Black rust of wheat is caused by Puccinia graminis tritici. The use of fungicide Dithane Z-78 and Dithane M-45 control the disease even at lower concentration. Loose smut of wheat is caused by Ustilago trittict. The use of fungicides (systemic fungicide like D-735 and F-461) give quite encouraging result