Leaf curl on Viburnum - Korean spice

We have a Korean spice 'Viburnum carlesii' in our garden. The flowers are very pretty and they smell divine. Most of the leaves curl up every spring and eventually turn brown looking scorched. Any ideas what it is and how to remedy it?

 

Curling probably aphids.

 

Thank you Ron.
Looking at the leaves I don't see anything. Would they just come and go? Aren't aphids sign of dryness?

 

Have a look at this.

http://forums2.gardenweb.com/forums/load/shrubs/msg051549512274.html

 

Very helpful, thank you very much Ron. It looks like it, but much worse.
Will try the recommend soap spray.