Looks more like white fly or other insect damage. You could try a horticultural oil spray, or even soapy water spray, applied in the evening. Be sure to get the bottom of the leaves, as that is where most eggs are laid, and larvae do their destructive chomping.

Thanks! That makes sense, there are a few black spots on the bottoms of the leaves that looked like they were left behind by insects. I'll be sure to post pictures when(if) I get blooms from my bigger dahlias!

Thrip damage, possibly. Look inside the flowers to find her hiding deep in the petals.

Here's a useful ink on the subject of dahlia viruses.

http://www.dahlia.org/index.php?page=virus-research-w-wsu