Since the 1950s, Nicaragua has developed a culture of intensive pesticide use with considerable consequences for the environment, as well as human health. This article explores the roots of this culture of pesticide use. After World War II the availability of new products like DDT, combined with high prices for cotton on the international market, led to a drastic shift in agricultural practices. The article shows how experts from the United States, in Nicaragua under the auspices of President Truman’s Point Four Program, helped to facilitate the chemical revolution associated with the cotton boom.