I've burned rose leaves with neem. May have used it too strong. Try half of what is
recommended at first?

Potassium (sp) bicarbonate is good for fungus but you do have to apply it several times.

You can blast the aphids off with the hose. Then apply the neem.

For long term aphid prevention: plant chive, garlic, or onion next too the roses.
There is a book ("roses love garlic") which goes over this.
I planted a mix of ornamental chive, garlic and onions between the rose bushes.
Works great. And the garlic and onion have pretty flowers in the spring.
Periodically you have to pull up the garlic and onion as they get huge in the
nice rose soil. I just chopped up the root ball and replanted a quarter of the original.
Mulch or toss the remainder. They will stink up your garage. :-)

Judd