Pest is lying in shade (8)
I believe the answer is:
Here is my best explanation:
'pest' is the definition.
'is lying in shade' is the subsidiary indication.
'lying in' is an insertion indicator.
'shade' becomes 'nuance' ('nuance' can be a synonym of 'shade').
'is' placed into 'nuance' is 'nuisance'.
(Other definitions for nuisance that I've seen before include "Troublesome and annoying person", "Troublesome thing", "One causing annoyance", "Bothersome pest", "Bothersome annoying person", "Thing causing annoyance", "Irritation or pest", "Pest or irritation", "Annoyance" and "Something which annoys".)