Terri, I use a 2gal. hand pump sprayer by Gilmour. They're available from any Ace (or DG) hardware store and come with a lifetime warranty, made in the USA for about $20. Also available online. The spray is adjustable from a fine mist (good for getting the backs of hte leaves) to a coarse shower. I do lots of spraying because I grow orchids, which are hanging up in my pool cage, so they get watered and fertilized regularly by spraying.
That does look like a fungal blight of some sort to me. My cannas usually get a rusty fungus though, not as large or black spots as yours.
