Controlling black leaf streak disease (BLSD) in banana: the case of Costa Rica

The main foliar disease in bananas is black leaf streak disease (BLSD), also known as black Sigatoka, which is caused by the fungus Pseudocercospora fijiensis. Since most commercial banana varieties are susceptible to BLSD, the disease can only be controlled in the wet tropics, with frequent fungicide applications. Although systemic fungicides have played a key role in disease control, increases in fungicide resistance in P. fijiensis populations has lowered the efficacy of treatments and consequently resulted in increased frequencies of fungicide applications. This development raises serious questions concerning sustainable disease control, occupational health, and environmental risks. This chapter reviews the history of BLSD control in Costa Rica, with a focus on the use of demethylation inhibitors. This review can be used as an example to underscore the need for alternative and sustainable disease control methods in global banana production.