 Complete the following phrase:  After its introduction from South America to Spain in the late 1500s, the potato became a staple crop throughout Europe by the late 1700s. The potato allowed farmers to produce more food, and initially added variety to the European diet. The increased supply of food reduced disease, increased births and reduced mortality, causing a population boom throughout the British Empire, the US and Europe. The introduction of the potato also brought about the first intensive use of fertilizer, in the form of guano imported to Europe from Peru, and the first artificial pesticide, in the form of an arsenic compound used to fight Colorado potato beetles. Before the adoption of the potato as a major crop, the dependence on grain had caused repetitive regional and national famines when the crops failed, including 17 major famines in England between 1523 and 1623. The resulting dependence on the potato however caused the European Potato Failure, a disastrous crop failure from disease that resulted in widespread 