Cherry Laurel Scale
White prunicola scale, a sucking insect is often found on cherry laurel. http://extension.umd.edu/hgic/plants/armored-hard-scale-trees-and-shrubs
Here is some information on control. Monitor your shrubs to see what the infestation looks like, heavy, light, etc. Heavy infestations usually begin on outer branches. Dieback begins on small branches preceded by leaf yellowing and premature leaf drop. Prune out any dead or dying branches. Look for white scales on the bark and remove with a soft brush.
Check for crawlers starting in May (there may be three generations and they are salmon colored) before you spray. Wrap some of the branches with double-sided sticky tape to monitor for crawlers. When you see the crawlers, spray with a summer rate of horticultural oil. Follow all label directions. Do not spray when temperatures are in the high '80s in hot weather.
If this is not what you are noticing send us photos of the whole shrub, affected foliage, and stems.