Photo: Shutterstock Black Sigatoka, which is caused by a leaf fungus called Pseudocercospora fijensis, affects banana plantations across the globe. To protect their harvest, banana farmers use fungicides, but increasing quantities are needed. This is due to the fungus’ increased resistance against the deployed fungicides, Wageningen researchers state in the Pest Management Science journal.
This is the first time the researchers conducted an extensive analysis of the leaf fungus’ isolates (variants) sensitivity to three fungicides that are frequently used in banana-producing countries such as Colombia, Costa Rica, the Dominican Republic, Ecuador, the Philippines, Guadeloupe, Martinique and Cameroun. Their research shows that the fungus is rapidly developing a resistance to fungicides as a result of the liberal use of these chemicals. Isolates of Black Sigatoka on banana plantations that were not sprayed with fungicides retained their sensitivity to the products.
Vicious circle
Research leader Gert Kema, professor of Phytopathology in Wageningen, states that the banana producers must break free of the vicious circle of increased use of fungicides which leads to increased resistance in the destructive fungus. For many years, he has called for research and development of new banana breeds resistant to Black Sigatoka and the development of alternative methods of disease control.
Banana is the most consumed fruit in the world. Banana plantations almost exclusively cultivate the Cavendish banana. This variety, which makes up some 95% of the global export, is highly susceptible to Black Sigatoka. This is why the farmers spray their crop with fungicides on a weekly basis. This makes banana production very vulnerable and not at all sustainable. Moreover, part of the banana growers is faced with another encroaching fungus: the aggressive soil fungus Panama Disease.
Resistant varieties
Kema joined a consortium last year with the Bill and Melinda Gates Foundation and Wageningen Biotech company Keygene to develop banana varieties resistant to Panama Disease. Additionally, with the help of international funding, he launched a business to develop varieties resistant to Black Sigatoka. Previously, Kema’s group mapped the resistance of hundreds of (wild) banana varieties against fungal diseases.
