I love nasturtiums and have grown them for the past 30 years.
Don't know what to tell you about the bugs. All mine have ever been bothered by were black aphids, and that was only for one season. I have heard, though, that nasturtiums are very attractive to aphids, so much so that some people use them as "aphid traps" to lure the pests away from the veggie garden.
They do best with a little neglect. You don't want to feed them, or you'll end up with lots of pretty leaves and few, if any, flowers. They also don't like a lot of water. I only water mine when they begin to look like they're on the verge of wilting. That can be as infrequently as once a week or less during cool weather, or as often as every day if the temperature gets over 100Ã‚Âº.
"Isn't it enough to see that a garden is beautiful without having to believe that there are fairies at the bottom of it too?" - Douglas Adams