Panama disease is caused by a Fusarium fungus. One of the Fusarium fungus stems, known as Tropical Race 4 (TR4) infects a lot of local banana varieties, but also the Cavendish banana which is worth 85% of the global trade. The fungus infects the roots, affects the vascular system and finally kills the plant. Once a plot has been infected, further cultivation of bananas is impossible.
Because the banana sector is dominated by one variety, the sector is extremely vulnerable. All modern bananas are clones of one another, there is barely any variation. The Cavendish banana is extremely susceptible to TR4, a type of the fusarium fungus that reared its head a few years ago. This means the fungus is threatening the global monoculture of Cavendish bananas and a lot of other local varieties.
After sampling missions the fungus was isolated from infected plants and then studied further through DNA analysis. Through determining the number and the nature of mutations in the fungi, researchers were able to see exactly what branches were related. "The necessity of quarantine measures to prevent international spreading and the importance of sustainable solutions are once again underlined with this," according to Gert Kema, special professor of Tropical Phytopathology at Wageningen University.
Dependent on the banana
The banana is the third most important food crop in developing countries besides wheat, rice and maize. It is also the world's most eaten fruit. It is popular in the West but for those living in the tropics the banana is often the main food source. Millions of farmers are dependent on a good harvest. It is increasingly threatened by the TR4 fungus.
The research was carried out by Wageningen University & Research in collaboration with foreign scientists and was published on March 22 2018 in Frontiers in Plant Science and can be viewed here