that's csing majoroncern in uador -- banas a theus. euntry's nuer one eort.the days reporter: no, there's not an airport ahead. the sign is warning drivers about low-flying aircraft, spraying banana fields in southern ecuador with fungicides as a preventive measure. they make their runs two or three times a week. their target is black sigatoka, a fungus that is to bananas what bubonic plague once was to humans. darwin palacios owns four conventional non-organic banana plantations. it's a family business. darwin: black sigatoka is not a disease you can eradicate. you have to learn how to live with it. it will always be there. it's a fungus that thrives under these favorable, humid nditions. all we can do is carry out regular checks to make sure there isn't an outbreak that will damage thbanana crop. and make sure that the leaves and the fruit stay healthy. reporter: once the fungus has taken hold, it's hard to fight. ecuador has been mainly spared so far, due to its climate not being as humid and rainy as central america, for example, w