I recommend using some Bayer advanced neem oil for an insecticide. Its organic, and as long as you use it at dawn or dusk (no direct sunlight) it wont do any harm to the plants. I think it says 1-3oz per gallon of water on the bottle, and only apply it once or twice a week. If you use dish soap make sure its biodegradable.

But you say that your leaves are curled up and white? To me it sounds like a mold or powdery mildew. This is usually caused by rain, over spraying with the insecticide, or really humid climates. It could also be some type of deficiency but I couldnt tell you until I see the pics. Try uploading them from your computer instead by clicking the tree icon above the text box.