In 1965, Chavez led the United Farm Workers during a national and international boycott of California table grapes that led to a landmark contract for farmworkers, signed on July 29, 1970, by 26 growers in Delano, California, including Giumarra Vineyards, the leading table-grape grower. Later in the decade, the union helped outlaw the use of the short-handled hoe, el cortito, because it required laborers to stoop in the fields for hours on end. In the ’80s, the United Farm Workers opened health clinics and launched a “Wrath of Grapes” campaign that drew attention to the harms of DDT and other pesticides.