The spray needs to be a systemic and repeated regularly to catch the different stages of the life cycle. the adults will have laid eggs . these arent affected by the spray. the adults do die and you think the plant is clear. the eggs hatch and grow into adults and you are back to the beginning of the angst.

Provado is the best that I know of on ornamentals. On edibles, you are pretty much stuck with spraying thoroughly every three days with proprietary insecticidal soap, or an organic brand of washing up fluid.