Hi, I have about 10 plants on my balcony in Barcelona. When my plants were still small (3rd set of leaves) I noticed some of the leaves developing tiny white spots which give the leaves a kind of powdered look. I noticed it spreading and so started spraying with a soap mixture. I transplanted to bigger pots and continued spraying but the white spots didn't go away. I then applied an insecticide which attacks 'sap sucking' beasties. The infected areas then became see-through. The problem is that the leaves died as well as the bugs. I now have plants that have no bottom foliage and the white spots are appearing again on the top healthy leaves! What are these bugs and how can I remove them without killing the leaves? Please help!