Posted: 07/07/2012 at 13:21
Are you sure they're wooly aphids ? Normally you'd find them on the undersides of leaves rather than on branches / new growth.
Why are you worried about a systemic insecticide affecting the fruit? Are you planning on making crab apple jelly? If so, I would not use a systemic - I wouldn't want insecticide in anything i was planning to eat.
I've used SB Plant Invigorator on wooly aphid recently (if that is what you've got) - spray thoroughly every few days for a week, then weekly for a few more weeks until they're all dead.