Black leaf streak (Mycosphaerella fijiensis Morelet) is responsible for losses in banana production. Facing a growing demand for products that are less harmful to the environment and the economy, the search for natural alternatives is of great importance. The objective of this study was to determine the efficiency of three nutritive and inoculated liquid fertilizers with natural antagonistic microorganisms as a more sustainable approach for the biological control of the pathogen. The liquid fertilizers were sprayed onto the plants with a hand-held electrostatic pump, which represents an innovation in the way fungicides are sprayed in banana plantations. The liquid fertilizers showed a growth of bacteria on the phylloplane of the leaves, which over time could have an influence on the reduction of the infection severity. Information was gathered on how an increase in the population of bacteria could have a positive impact on the health of the plant and the environment, thus helping to reduce the dependency on agrochemicals.