New study shows decreasing effectiveness of fungicides to control Black Sigatoka banana disease The fungus Pseudocercospora fijiensis causes black leaf streak disease or Black Sigatoka of banana, which is the most damaging leaf disease of bananas worldwide. An analysis of 592 P. fijensis isolates from seven banana-producing countries on three continents shows how P. fijensis is evolving to insensitivity to azole fungicides due to the heavy use of pesticides. The results of the study have been published in Pest Management Science and underscore the need to stop this vicious circle by developing alternative disease control methods and new banana varieties. Black leaf streak disease is the most important banana disease worldwide. Cavendish bananas represent more than 50% of the global production - and dominate the export (95%) – but are very susceptible to this disease. In most countries, banana production relies on continual intensive disease control, usually at weekly intervals, throughout the year. It demonstrates the fragility of global banana production and its overall unsustainability. Azole fungicides are the cornerstone for fungal disease control in plants, animals and humans.