Dandruff on my bay trees

I have 3 bay trees in pots which I have had for some years without a problem.
After giving them a light prune/tidy up I noticed the young leaves are curled up and sticky.
There is also specks of what looks like white dandruff over the leaves !! which comes off by shaking the plant, its not white fly.
Could anyone give me advice as to what it is, and what to do.
Many thanks.

 

Bay Suckers? http://www.telegraph.co.uk/gardening/gardeningadvice/8697452/The-bay-sucker.html

N.B. If you spray, read instructions about how long before you can use the leaves in cooking and you might wish to pick a few beforehand.

 

That's interesting,Thanks for that @Scrungee ,I've had similar on my Buxus and have put it down to white fly but on reading up there's such a thing as Box Suckers too,so now I know

 

Not had it on our Bay for a few years. We scrounged leaves for cooking from a neighbour's Bay after spraying. Scale Insects are normally the worst pest on it.