In the 19th century, which substances were used to deter the picking of grape vines?

The correct answer is lime and copper sulfate because these substances were commonly employed in viticulture during the 19th century for various purposes, including the prevention of diseases and pests that could affect grape vines. Lime was used to increase soil pH and improve growing conditions, while copper sulfate acted as a fungicide, particularly against diseases like downy mildew, which were detrimental to grape production.

Pyrethrum and nicotine, while effective insecticides, were not specifically noted for use in grape vineyard management in the 19th century. Organophosphates and DDT are modern synthetic pesticides that were developed much later in the 20th century and have no historical relevance to 19th-century practices. Sulfur and hellabore were also involved in agricultural practices but were not the primary substances used for deterring the picking of grape vines as effectively as lime and copper sulfate.