Panama disease

Panama disease, a Fusarium wilt, is a banana plant disease caused by the fungus Fusarium oxysporum. The fungus attacks the roots of the banana plant. The disease is resistant to fungicide and cannot be controlled chemically.

Gros Michel or 'Big Mike' was an early export cultivar of banana. This cultivar was wiped out by Panama disease in the 1950s. The disease first appeared in Suriname, then made its way to the Caribbean, and, by the 1920s, to Honduras, the world's largest producer of bananas at the time. Although there are many banana cultivars, Gros Michel was especially suitable for export to non-tropical nations. A search for a substitute located the Vietnamese Cavendish cultivar, which is resistant to the disease. However, more care is required for shipping the Cavendish banana, and its quality compared to Gros Michel is debated.

Recently, a new strain called 'tropical race four Panama disease' has begun to attack Cavendish banana plants in south Asia. Given the high volume of modern international trade, banana producers expect this strain to spread through Africa and into South America and the Caribbean.

Plant breeders and geneticists are trying to develop new cultivars that are resistant to this new strain of Panama disease. Unfortunately, such efforts are progressing slowly because the triploid banana cultivars selected for human consumption are seedless and reproduce asexually, which decreases genetic variation and makes breeding difficult.