Hello, Joselu. I believe that the white fly has nothing to do with the rot of the fruit. This mosquito damages the leaves: it introduces the sting and sucks the sweat. Similarly, it leaves a sweet residue that will be attacked by a black fungus. As a result of this attack, everything becomes black and the leaf will not be able to do its job, that is, to create food to supply the plant using the energy of light. This black layer can also appear on the fruits, but it will not be a putrefaction. You may have seen white flies on a rot, but rot will have been produced by something else. So there are two things that rot and a fly. Let's see if we can figure out what those putrefactions do. Can you send any photos or other information?