Numerous spices, fruits, and vegetables are grown in Grenada. The principal crops for export are nutmeg and mace, bananas, cocoa beans, and other fresh fruits and vegetables. Production in 1999 included bananas, 4,000 tons; cocoa, 1,000 tons; and avocados, 2,000 tons. Banana production decreased in the 1980s due to the appearance of Moko disease. There are small scattered plots of cotton, cloves, limes, nutmeg, cinnamon, and coffee. Both cotton and lime oil are produced on Carriacou. Food crops consist of yams, sweet potatoes, corn, peas, and beans. Grenada is especially known for its nutmeg production, earning it the nickname "Spice Island." Prices for nutmeg, however, have been rather low in recent years due to a soft market and the collapse of the Grenada/Indonesia cartel in 1990. Late in 1991, Grenada and Indonesia (the world's largest nutmeg producer) signed a new cartel agreement which aims to constrict production, thereby driving up world prices for the spice. In 2001, exports of agricultural products amounted to US $20.8 million.