A contentious practice, aerial spraying is nevertheless considered by many as the most efficient way of applying fungicides in commercial banana plantations. Planes and helicopters can treat large areas faster than ground-based methods, which helps slow down disease development. Although technological innovations have helped reduce the volumes of fungicides and improve accuracy, the treatment will less efficient if the weather conditions are not optimal for spraying.
Nozzles that open and close automatically in sensitive zones (inhabitated areas and streams and rivers) reduces the volumes of fungicides used. If the mapping is precise, the technology also protects the environment and public health.
Thanks to the Global Positioning System, it's possible to register the plots scheduled for treatment and to calculate more precisely the volumes of fungicides needed to cover the targeted area.
Coupled with GPS, geographical information systems help localize areas to avoid, such as protected areas, electrical cables and inhabited zones.
This tool automatically controls the volume to apply per hectare. Depending on the speed and position of the plance, the software calculates and adjusts the volume of fungicide to apply in real time. The coverage is more homogenous and as a result the treatment more effective. The technology is already available for other crops.
Proponents of ground spraying argue that it is more efficient than aerial spraying in reaching the underside of the leaves where lesions first develop. On the other hand, it poses a greater health risk to the operators.
Electrostatic sprayers have increased the efficiency of traditional sprayers. Compressed air that is given a negative electric charge as it travels through the nozzle, helps to create more uniformly sized droplets that disperse well because they repel each other. When charged droplets strike a surface, they create a momentary overcharge that repels other particles.
Still at the prototype stage, this machine is being developed to replace aerial spraying. It can currently cover 8 hectares in an hour, compared to 40 for the helicopter.
This method consists in placed a dose of fungicide at the leaf axil (the angle between the leaf and the pseudostem) using a spotgun. Brazilian growers have been experimenting with the method.