Hi Judy,
Aphids can show up very fast, but what you have might be white flies... look remarkably like little dead bug bodies - and rarely move around. Aphids are easy to see, light lime green and usually a ton of them surrounding new growth and buds.

Rust can spread, and quickly to your other plants. If it is rust, I would definatly remove foliage and start using a fungicide. There are lots of sites and studies concering the effectiveness of certian fungicides on rust, but the cheapest effective one mentioned in these studies that I can readily find is Chlorothalonil.

Lots of people here can give you other remedies (fungicide recs). They are usually really helpful... I recommend looking through other threads here... unfortunately, I can't get the search function to work for me lately...so you might have to do it page by page...

Wipe the foliage with white tissue, if you get orange streaks, it's rust.

Run down to your Lowe's or Home Depot and look for Bayer 'All in One' or 'Two in One'. It's a combination systemic insecticide and fungicide. The 'All in One' includes a fertilizer. Cut back the foliage on the plants that have rust. Apply the product.

The aphids will leave their spent skins on the foliage and as the foliage grows, the skins get higher until something knocks them off. Open the foliage carefully down in the center and see if you find the little green, translucent aphids there.

Good luck, Ed