Regulate misuse of pesticide — it'd cut corners etc (3,6)
I believe the answer is:
set pieces
'corners etc' is the definition.
(I know this)
'regulate misuse of pesticide it'd cut' is the wordplay.
'regulate' becomes 'set' (regulate can mean to set standards or rules).
'misuse of' indicates anagramming the letters (I've seen this in other clues).
'cut' suggests deleting specific letters.
'pesticide' with 'itd' removed is 'pescie'.
'pescie' anagrammed gives 'pieces'.
'set'+'pieces'='SET PIECES'
(Other definitions for set pieces that I've seen before include "men on chess board?" , "Elaborate formal speeches" , "Well-practised moves" , "rehearsed moves" , "fireworks displays" .)