Bad News for Banana Lovers
April 25, 2014
The world’s $5-billion banana crop is being threatened by a devastating fungal disease that has already spread from Asia to Africa and the Middle East and is menacing Latin America, according to the United Nations Food and Agriculture Organization (FAO). The fungus, Tropical Race 4 (TR4), causes a variety of a well-known banana disease called Fulsarium wilt, also known as Panama disease. Although exact figures are unavailable, scientists estimate that TR4 has already caused tens of millions of dollars in damage. According to the FAO, bananas are the eighth most important food crop in the world and the fourth most important in developing nations. “Countries need to act now if we are to avoid the worst-case scenario, which is massive destruction of much of the world’s banana crop,” warned a FAO plant pathologist. FAO officials are strongly urging countries to improve their efforts to detect and report cases of the disease as well as their preventive measures.
The fruit produced by banana trees infected with TR4 is still edible. But the trees turn a sickly yellow as they wither and die. Current methods of fighting fungal diseases, including fungicides, cannot eliminate TR4, which lives in the soil and can last for decades. For this reason, agricultural officials are emphasizing the need for stricter preventive efforts.
Bananas overflow a stall at an outdoor market in Jamaica. Bananas are the fourth most important food crop in developing countries. (© Marilyn Martin, Index Stock)
TR4 is not new to agriculture. But it has become increasingly dangerous because of changes in the banana industry. Until recent decades, Asian planters cultivated various banana varieties. On such plantations, the appearance of any one fungus, including TR4, caused relatively little damage. However, the TR4-susceptible Dwarf Cavendish now dominates the international banana trade. Banana growers turned to the Dwarf Cavendish in the 1900′s after the then-popular Gros Michel banana became susceptible to two other races (varieties) of the fungus that causes Fulsarium wilt. Planters embraced the Dwarf Cavendish because in addition to being resistant to races 1 and 2, it does not bruise easily or ripen quickly—advantages for bananas being shipped internationally. With the widespread cultivation of Dwarf Cavendish bananas, TR4 has now become a serious threat.
So far, agricultural scientists have been unable to produce a hybrid or genetically modified variety of the Dwarf Cavendish that resists TR4. Many experts argue that the only way to save the banana industry is by cultivating a greater number of the more than 1,000 known varieties of the fruit.
