Mine have never been overwhelmed by any disease they have caught. I've usually been able to still harvest fruit even though the plant had some spots on some of the leaves or flowers. Mine seem to catch any and all of the tomato/potato/eggplant diseases.

I'm a few states north and mine never have the same flavor as they did in Colombia. Down there I only saw them growing high in the hills where it is much cooler. Here I have better luck growing them in part sun where it is cooler.