I am going to let my Tree Hugger side come out and suggest imidacloprid as a Preventive. In fact if the aphids aren't too bad I might use it as a Curative. The Idea is imidacloprid only controls bad insects and not the Predator insects.
IPM stands or I Pay Materials (in my book at least). To me good IPM is preventative treatment of a good systemic that only effects the bad insects. I try to Up Sell Ornamental Shrub Pest Control because it is so easy and PROFITABLE.
"As Americans you have the right to be stupid." John Kerry
"Life is tough, but it's tougher when you're stupid.” John Wayne.