Yep!

Power hose them off, then repeat as needed.

They appear to be. Control can be achieved by knocking the wee buggers off with a sharp stream of water, a power hose is not necessary and may cause more damage then the Aphids. I use a 1 quart spray bottle similar to one that window washing sprays come in.
The link below provides a great deal of very good information about Aphids.

Here is a link that might be useful: About Aphids

Okay, so call it a harsh water spray.